2007 guideline for isolation precautions: preventing transmission of infectious agents in health care settings Jane D. Siegel, MD, Emily Rhinehart, RN, MPH, CIC, Marguerite Jackson, PhD, Linda Chiarello, RN, MS, for the Health Care Infection Control Practices Advisory Committee Health Care Infection Control Practices Advisory Committee (HICPAC) Chair Patrick J. Brennan, MD, Professor of Medicine, Divi- sion of Infectious Diseases, University of Pennsylvania Medical School Executive Secretary Michael Bell, MD, Division of Health Care Quality Promotion, National Center for Infectious Diseases, Centers for Disease Control and Prevention Members Vicki L. Brinsko, RN, BA, Infection Control Coordina- tor, Vanderbilt University Medical Center E. Patchen Dellinger, MD, Professor of Surgery, Uni- versity of Washington School of Medicine Jeffrey Engel, MD, Head, General Communicable Disease Control Branch, North Carolina State Epidemiologist Steven M. Gordon, MD, Chairman, Department of Infections Diseases, Hospital Epidemiologist, Cleveland Clinic Foundation Lizzie J. Harrell, PhD, D(ABMM), Research Professor of Molecular Genetics, Microbiology and Pathology, Associate Director, Clinical Microbiology, Duke Univer- sity Medical Center Carol O’Boyle, PhD, RN, Assistant Professor, School of Nursing, University of Minnesota David Alexander Pegues, MD, Division of Infec- tious Diseases, David Geffen School of Medicine at UCLA Dennis M. Perrotta, PhD, CIC, Adjunct Associate Pro- fessor of Epidemiology, University of Texas School of Public Health, Texas A&M University School of Rural Public Health Harriett M. Pitt, MS, CIC, RN, Director, Epidemiology, Long Beach Memorial Medical Center Keith M. Ramsey, MD, Professor of Medicine, Medical Director of Infection Control, Brody School of Medicine, East Carolina University Nalini Singh, MD, MPH, Professor of Pediatrics, Epi- demiology and International Health, George Washing- ton University Children’s National Medical Center Kurt Brown Stevenson, MD, MPH Division of Infec- tious Diseases, Department of Internal Medicine, Ohio State University Medical Center Philip W. Smith, MD, Chief, Section of Infectious Dis- eases, Department of Internal Medicine, University of Nebraska Medical Center HICPAC membership (past) Robert A. Weinstein, MD (Chair), Cook County Hos- pital, Chicago, IL Jane D. Siegel, MD (Co-Chair), University of Texas Southwestern Medical Center, Dallas, TX Michele L. Pearson, MD (Executive Secretary), Centers for Disease Control and Prevention, Atlanta, GA Raymond Y.W. Chinn, MD, Sharp Memorial Hospital, San Diego, CA Alfred DeMaria, Jr, MD, Massachusetts Department of Public Health, Jamaica Plain, MA James T. Lee, MD, PhD, University of Minnesota, Minneapolis, MN William A. Rutala, PhD, MPH, University of North Carolina Health Care System, Chapel Hill, NC William E. Scheckler, MD, University of Wisconsin, Madison, WI Beth H. Stover, RN, Kosair Children’s Hospital, Louis- ville, KY Marjorie A. Underwood, RN, BSN CIC, Mt Diablo Medical Center, Concord, CA (Am J Infect Control 2007;35:S65-164.) 0196-6553/$32.00 This is a U.S. Government work. There are no restrictions on its use. doi:10.1016/j.ajic.2007.10.007 S65
100
Embed
2007 guideline for isolation precautions: preventing ......2007 guideline for isolation precautions: preventing transmission of infectious agents in health care settings Jane D. Siegel,
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
2007 guideline for isolation precautions:preventing transmission of infectiousagents in health care settingsJane D. Siegel, MD, Emily Rhinehart, RN, MPH, CIC, Marguerite Jackson, PhD, Linda Chiarello, RN, MS, for the HealthCare Infection Control Practices Advisory Committee
Health Care Infection Control Practices AdvisoryCommittee (HICPAC)
ChairPatrick J. Brennan, MD, Professor of Medicine, Divi-
sion of Infectious Diseases, University of PennsylvaniaMedical School
Executive SecretaryMichael Bell, MD, Division of Health Care Quality
Promotion, National Center for Infectious Diseases,Centers for Disease Control and Prevention
MembersVicki L. Brinsko, RN, BA, Infection Control Coordina-
tor, Vanderbilt University Medical CenterE. Patchen Dellinger, MD, Professor of Surgery, Uni-
versity of Washington School of MedicineJeffrey Engel, MD, Head, General Communicable
Disease Control Branch, North Carolina StateEpidemiologist
Steven M. Gordon, MD, Chairman, Department ofInfections Diseases, Hospital Epidemiologist, ClevelandClinic Foundation
Lizzie J. Harrell, PhD, D(ABMM), Research Professorof Molecular Genetics, Microbiology and Pathology,Associate Director, Clinical Microbiology, Duke Univer-sity Medical Center
Carol O’Boyle, PhD, RN, Assistant Professor, Schoolof Nursing, University of Minnesota
David Alexander Pegues, MD, Division of Infec-tious Diseases, David Geffen School of Medicine atUCLA
(Am J Infect Control 2007;35:S65-164.)
0196-6553/$32.00
This is a U.S. Government work. There are no restrictions on its use.
doi:10.1016/j.ajic.2007.10.007
Dennis M. Perrotta, PhD, CIC, Adjunct Associate Pro-fessor of Epidemiology, University of Texas School ofPublic Health, Texas A&M University School of RuralPublic Health
Harriett M. Pitt, MS, CIC, RN, Director, Epidemiology,Long Beach Memorial Medical Center
Keith M. Ramsey, MD, Professor of Medicine, MedicalDirector of Infection Control, Brody School of Medicine,East Carolina University
Nalini Singh, MD, MPH, Professor of Pediatrics, Epi-demiology and International Health, George Washing-ton University Children’s National Medical Center
Kurt Brown Stevenson, MD, MPH Division of Infec-tious Diseases, Department of Internal Medicine, OhioState University Medical Center
Philip W. Smith, MD, Chief, Section of Infectious Dis-eases, Department of Internal Medicine, University ofNebraska Medical Center
HICPAC membership (past)Robert A. Weinstein, MD (Chair), Cook County Hos-
pital, Chicago, ILJane D. Siegel, MD (Co-Chair), University of Texas
Southwestern Medical Center, Dallas, TXMichele L. Pearson, MD (Executive Secretary),
Centers for Disease Control and Prevention, Atlanta,GA
Raymond Y.W. Chinn, MD, Sharp Memorial Hospital,San Diego, CA
Alfred DeMaria, Jr, MD, Massachusetts Departmentof Public Health, Jamaica Plain, MA
James T. Lee, MD, PhD, University of Minnesota,Minneapolis, MN
William A. Rutala, PhD, MPH, University of NorthCarolina Health Care System, Chapel Hill, NC
William E. Scheckler, MD, University of Wisconsin,Madison, WI
Beth H. Stover, RN, Kosair Children’s Hospital, Louis-ville, KY
Marjorie A. Underwood, RN, BSN CIC, Mt DiabloMedical Center, Concord, CA
S65
S66 Vol. 35 No. 10 Supplement 2 Siegel et al
HICPAC LiaisonsWilliam B. Baine, MD, Liaison to the Agency for
Health Care Quality ResearchJoan Blanchard, RN, MSN, CNOR, Liaison to the
Association of Perioperative Registered NursesPatrick J. Brennan, MD, Liaison to the Board of Scien-
tific CounselorsNancy Bjerke, RN, MPH, CIC, Liaison to the Associa-
tion of Professionals in Infection Prevention andControl
Jeffrey P. Engel, MD, Liaison to the Advisory Commit-tee on Elimination of Tuberculosis
David Henderson, MD, Liaison to the National Insti-tutes of Health
Lorine J. Jay, MPH, RN, CPHQ, Liaison to the HealthCare Resources Services Administration
Stephen F. Jencks, MD, MPH, Liaison to the Centerfor Medicare and Medicaid Services
Sheila A. Murphey, MD, Liaison to the Food and DrugAdministration
Mark Russi, MD, MPH, Liaison to the AmericanCollege of Occupational and EnvironmentalMedicine
Rachel L. Stricof, MPH, Liaison to the Advisory Com-mittee on Elimination of Tuberculosis
Michael L. Tapper, MD, Liaison to the Society forHealth Care Epidemiology of America
Robert A. Wise, MD, Liaison to the Joint Commissionon the Accreditation of Health Care Organizations
Authors’ AssociationsJane D. Siegel, MD, Professor of Pediatrics, Depart-
ment of Pediatrics, University of Texas SouthwesternMedical Center
Marguerite Jackson, RN, PhD, CIC, Director, Admin-istrative Unit, National Tuberculosis CurriculumConsortium, Department of Medicine, University ofCalifornia San Diego
Linda Chiarello, RN, MS, Division of Health CareQuality Promotion, National Center for InfectiousDiseases, Centers for Disease Control and Pre-vention
TABLE OF CONTENTS
Executive SummaryAbbreviationsPart I: Review of the Scientific Data Regarding
Transmission of Infectious Agents in Health CareSettings
I.A. Evolution of the 2007 DocumentI.B. Rationale for Standard and Transmission-Based
Precautions in Health Care Settings
I.B.1. Source of Infectious AgentsI.B.2. Susceptible HostsI.B.3. Modes of Transmission
I.B.3.a. Contact TransmissionI.B.3.a.i. Direct Contact TransmissionI.B.3.a.ii. Indirect Contact Transmission
I.B.3.b. Droplet TransmissionI.B.3.c. Airborne TransmissionI.B.3.d. Emerging Issues and Controversies
Concerning Bioaerosols and Air-borne Transmission of InfectiousAgents
I.B.3.d.i. Transmission From PatientsI.B.3.d.ii. Transmission From the Envi-
ronmentI.B.3.e. Other Sources of Infection
I.C. Infectious Agents of Special Infection ControlInterest for Health Care SettingsI.C.1. Epidemiologically Important Organisms
SupportII.A.2. Institutional Safety Culture and Organiza-
tional CharacteristicsII.A.3. Adherence of Health Care Workers to Rec-
ommended GuidelinesII.B. Surveillance for Health Care–Associated In-
fectionsII.C. Education of Health Care Workers, Patients, and
FamiliesII.D. Hand HygieneII.E. Personal Protective Equipment for Health Care
WorkersII.E.1. GlovesII.E.2. Isolation GownsII.E.3. Face Protection: Masks, Goggles, Face
ShieldsII.E.3.a. MasksII.E.3.b. Goggles and Face Shields
II.E.4. Respiratory ProtectionII.F. Safe Work Practices to Prevent Health Care Worker
Exposure to Bloodborne PathogensII.F.1. Prevention of Needlesticks and Other
Sharps-Related InjuriesII.F.2. Prevention of Mucous Membrane Contact
II.F.2.a. Precautions During Aerosol-Gener-ating Procedures
II.G. Patient PlacementII.G.1. Hospitals and Long-Term Care SettingsII.G.2. Ambulatory Care SettingsII.G.3. Home Care
II.H. Transport of PatientsII.I. Environmental MeasuresII.J. Patient Care Equipment, Instruments/DevicesII.K. Textiles and LaundryII.L. Solid WasteII.M. Dishware and Eating UtensilsII.N. Adjunctive Measures
II.N.1. ChemoprophylaxisII.N.2. ImmunoprophylaxisII.N.3. Management of Visitors
II.N.3.a. Visitors as Sources of InfectionII.N.3.b. Use of Barrier Precautions by
Visitors
Part III. HICPAC Precautions to Prevent Transmis-sion of Infectious Agents
III.A. Standard PrecautionsIII.A.1. New Standard Precautions for Patients
III.A.1.a. Respiratory Hygiene/Cough Eti-quette
III.A.1.b. Safe Injection PracticesIII.A.1.c. Infection Control Practices for
III.C. Syndromic or Empiric Application of Transmis-sion-Based Precautions
III.D. Discontinuation of PrecautionsIII.E. Application of Transmission-Based Precautions in
Ambulatory and Home Care SettingsIII.F. Protective Environment
Part IV: RecommendationsAppendix A: Type and Duration of Precautions
Needed for Selected Infections and ConditionsGlossaryReferencesTable 1. Recent history of guidelines for prevention
of health care–associated infectionsTable 2. Clinical syndromes or conditions warrant-
ing additional empiric transmission-based precautionspending confirmation of diagnosis
Table 3. Infection control considerations for high-priority (CDC category A) diseases that may resultfrom bioterrorist attacks or are considered bioterroristthreats
Table 4. Recommendations for application of Stan-dard Precautions for the care of all patients in all healthcare settings
Table 5. Components of a protective environmentFig 1. Sequence for donning and removing personal
protective equipment
EXECUTIVE SUMMARY
The Guideline for Isolation Precautions: PreventingTransmission of Infectious Agents in Health Care Set-tings 2007 updates and expands the 1996 Guidelinefor Isolation Precautions in Hospitals. The followingdevelopments led to these revisions of the 1996guideline:
1. The transition of health care delivery from primar-ily acute care hospitals to other health caresettings (eg, home care, ambulatory care, free-standing specialty care sites, long-term care) cre-ated a need for recommendations that can beapplied in all health care settings using commonprinciples of infection control practice, yet canbe modified to reflect setting-specific needs.
S68 Vol. 35 No. 10 Supplement 2 Siegel et al
Accordingly, the revised guideline addresses thespectrum of health care delivery settings. Further-more, the term ‘‘nosocomial infections‘‘ is re-placed by ‘‘health care–associated infections’’(HAIs), to reflect the changing patterns in healthcare delivery and difficulty in determining the geo-graphic site of exposure to an infectious agent and/or acquisition of infection.
2. The emergence of new pathogens (eg, severe acuterespiratory syndrome coronavirus [SARS-CoV]associated with SARS avian influenza in humans),renewed concern for evolving known pathogens(eg, Clostridium difficile, noroviruses, community-associated methicillin-resistant Staphylococcus au-reus [CA-MRSA]), development of new therapies(eg, gene therapy), and increasing concern for thethreat of bioweapons attacks, necessitates address-ing a broader scope of issues than in previous isola-tion guidelines.
3. The successful experience with Standard Precau-tions, first recommended in the 1996 guideline,has led to a reaffirmation of this approach asthe foundation for preventing transmission of in-fectious agents in all health care settings. New ad-ditions to the recommendations for StandardPrecautions are respiratory hygiene/cough eti-quette and safe injection practices, including theuse of a mask when performing certain high-risk, prolonged procedures involving spinal canalpunctures (eg, myelography, epidural anesthesia).The need for a recommendation for respiratoryhygiene/cough etiquette grew out of observationsduring the SARS outbreaks, when failure to imple-ment simple source control measures with pa-tients, visitors, and health care workers (HCWs)with respiratory symptoms may have contributedto SARS-CoV transmission. The recommendedpractices have a strong evidence base. The contin-ued occurrence of outbreaks of hepatitis B andhepatitis C viruses in ambulatory settings indi-cated a need to reiterate safe injection practicerecommendations as part of Standard Precautions.The addition of a mask for certain spinal injec-tions grew from recent evidence of an associatedrisk for developing meningitis caused by respira-tory flora.
4. The accumulated evidence that environmentalcontrols decrease the risk of life-threatening fungalinfections in the most severely immunocompro-mised patients (ie, those undergoing allogeneichematopoietic stem cell transplantation [HSCT]) ledto the update on the components of the protectiveenvironment (PE).
5. Evidence that organizational characteristics (eg,nurse staffing levels and composition, establishment
of a safety culture) influence HCWs’ adherence torecommended infection control practices, and thusare important factors in preventing transmission ofinfectious agents, led to a new emphasis and recom-mendations for administrative involvement in thedevelopment and support of infection controlprograms.
6. Continued increase in the incidence of HAIscaused by multidrug-resistant organisms (MDROs)in all health care settings and the expandedbody of knowledge concerning prevention oftransmission of MDROs created a need formore specific recommendations for surveillanceand control of these pathogens that would bepractical and effective in various types of healthcare settings.
This document is intended for use by infectioncontrol staff, health care epidemiologists, health careadministrators, nurses, other health care providers,and persons responsible for developing, implement-ing, and evaluating infection control programs forhealth care settings across the continuum of care.The reader is referred to other guidelines and web-sites for more detailed information and for recom-mendations concerning specialized infection controlproblems.
PARTS I, II, AND III: REVIEW OF THE SCIENTIFICDATA REGARDING TRANSMISSION OFINFECTIOUS AGENTS IN HEALTH CARESETTINGS
Part I reviews the relevant scientific literaturethat supports the recommended prevention andcontrol practices. As in the 1996 guideline, themodes and factors that influence transmission risksare described in detail. New to the section on trans-mission are discussions of bioaerosols and of howdroplet and airborne transmission may contributeto infection transmission. This became a concernduring the SARS outbreaks of 2003, when transmis-sion associated with aerosol-generating procedureswas observed. Also new is a definition of ‘‘epidemi-ologically important organisms’’ that was developedto assist in the identification of clusters of infec-tions that require investigation (ie multidrug-resis-tant organisms, C difficile). Several other pathogensof special infection control interest (ie, norovirus,SARS, Centers for Disease Control and Prevention[CDC] category A bioterrorist agents, prions, mon-keypox, and the hemorrhagic fever viruses) alsoare discussed, to present new information and in-fection control lessons learned from experiencewith these agents. This section of the guideline
Siegel et al December 2007 S69
also presents information on infection risks associ-ated with specific health care settings and patientpopulations.
Part II updates information on the basic principles ofhand hygiene, barrier precautions, safe work practices,and isolation practices that were included in previousguidelines. However, new to this guideline is importantinformation on health care system components thatinfluence transmission risks, including those compo-nents under the influence of health care administrators.An important administrative priority that is described isthe need for appropriate infection control staffing tomeet the ever-expanding role of infection control pro-fessionals in the complex modern health care system.Evidence presented also demonstrates anotheradministrative concern: the importance of nurse staff-ing levels, including ensuring numbers of appropriatelytrained nurses in intensive care units (ICUs) for prevent-ing HAIs. The role of the clinical microbiology labora-tory in supporting infection control is described, toemphasize the need for this service in health care facil-ities. Other factors that influence transmission risks arediscussed, including the adherence of HCWs to recom-mended infection control practices, organizationalsafety culture or climate, and education and training.
Discussed for the first time in an isolation guidelineis surveillance of health care–associated infections.The information presented will be useful to new infec-tion control professionals as well as persons involvedin designing or responding to state programs for publicreporting of HAI rates.
Part III describes each of the categories of precau-tions developed by the Health Care Infection ControlPractices Advisory Committee (HICPAC) and the CDCand provides guidance for their application in varioushealth care settings. The categories of Transmission-Based Precautions are unchanged from those in the1996 guideline: Contact, Droplet, and Airborne. Oneimportant change is the recommendation to don theindicated personal protective equipment (PPE—gowns,gloves, mask) on entry into the patient’s room for pa-tients who are on Contact and/or Droplet Precautions,because the nature of the interaction with the patientcannot be predicted with certainty, and contaminatedenvironmental surfaces are important sources fortransmission of pathogens. In addition, the PE for pa-tients undergoing allogeneic HSCT, described in previ-ous guidelines, has been updated.
TABLES, APPENDICES, AND OTHERINFORMATION
Five tables summarize important information.Table 1 provides a summary of the evolution of this
document. Table 2 gives guidance on using empiricisolation precautions according to a clinical syndrome.Table 3 summarizes infection control recommenda-tions for CDC category A agents of bioterrorism. Table 4lists the components of Standard Precautions and rec-ommendations for their application, and Table 5 listscomponents of the PE.
A glossary of definitions used in this guideline also isprovided. New to this edition of the guideline is a figureshowing the recommended sequence for donning andremoving PPE used for isolation precautions to opti-mize safety and prevent self-contamination duringremoval.
APPENDIX A: TYPE AND DURATION OFPRECAUTIONS RECOMMENDED FOR SELECTEDINFECTIONS AND CONDITIONS
Appendix A provides an updated alphabetical list ofmost infectious agents and clinical conditions forwhich isolation precautions are recommended. A pre-amble to the appendix provides a rationale for recom-mending the use of 1 or more Transmission-BasedPrecautions in addition to Standard Precautions, basedon a review of the literature and evidence demonstrat-ing a real or potential risk for person-to-person trans-mission in health care settings. The type and durationof recommended precautions are presented, with addi-tional comments concerning the use of adjunctivemeasures or other relevant considerations to preventtransmission of the specific agent. Relevant citationsare included.
PREPUBLICATION OF THE GUIDELINE ONPREVENTING TRANSMISSION OF MDROS
New to this guideline is a comprehensive review anddetailed recommendations for prevention of trans-mission of MDROs. This portion of the guidelinewas published electronically in October 2006 andupdated in November 2006 (Siegel JD, Rhinehart E,Jackson M, Chiarello L and HICPAC. Managementof multidrug-resistant organisms in health care set-tings, 2006; available from http://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline2006.pdf), and isconsidered a part of the Guideline for Isolation Pre-cautions. This section provides a detailed review ofthe complex topic of MDRO control in health caresettings and is intended to provide a context forevaluation of MDRO at individual health care set-tings. A rationale and institutional requirements fordeveloping an effective MDRO control program aresummarized.
Table 1. History of guidelines for isolation precautions in hospitals*
Year (reference) Document issued Comments
19701095 Isolation Techniques for Use in Hospitals, 1st ed d Introduced 7 isolation precaution categories with color-coded cards:
strict, respiratory, protective, enteric, wound and skin, discharge, and
blood.
d No user decision making required.
d Simplicity a strength; overisolation prescribed for some infections.
19751100 Isolation Techniques for Use in Hospitals, 2nd ed d Same conceptual framework as first edition.
19831097 Guideline for Isolation Precautions in Hospitals d Provided 2 systems for isolation: category-specific and disease-
specific.
d Protective isolation eliminated; blood precautions expanded to
include body fluids.
d Categories included strict, contact, respiratory, acid-fast bacteria,
enteric, drainage/secretion, blood and body fluids.
d Emphasized decision making by users.
1985-88778, 894 Universal Precautions d Developed in response to the HIV/AIDS epidemic.
d Dictated application of blood and body fluid precautions to all
patients, regardless of infection status.
d Did not apply to feces, nasal secretions, sputum, sweat, tears, urine,
or vomitus unless contaminated by visible blood.
d Added personal protective equipment to protect health care
workers from mucous membrane exposures.
d Handwashing recommended immediately after glove removal.
d Added specific recommendations for handling needles and other
sharp devices; concept became integral to the OSHA’s 1991 rule on
occupational exposure to blood-borne pathogens in health care
settings.
19871098 Body Substance Isolation d Emphasized avoiding contact with all moist and potentially infectious
body substances except sweat even if blood not present.
d Shared some features with Universal Precautions.
d Weak on infections transmitted by large droplets or by contact with
dry surfaces.
d Did not emphasize need for special ventilation to contain airborne
infections.
d Handwashing after glove removal not specified in the absence of
visible soiling.
19961 Guideline for Isolation Precautions in Hospitals d Prepared by the Healthcare Infection Control Practices Advisory
Committee.
d Melded major features of Universal Precautions and body substance
isolation into Standard Precautions to be used with all patients at all
times.
d Included 3 transmission-based precaution categories: Airborne,
Droplet, and Contact.
d Listed clinical syndromes that should dictate use of empiric isolation
until an etiologic diagnosis is established.
*Derived from Garner and Simmons.1099
Although the focus of this guideline is on measuresto prevent transmission of MDROs in health care set-tings, information concerning the judicious use of anti-microbial agents also is presented, because suchpractices are intricately related to the size of the reser-voir of MDROs, which in turn influences transmission(eg, colonization pressure). Two tables summarize
recommended prevention and control practices using7 categories of interventions to control MDROs: admin-istrative measures, education of HCWs, judiciousantimicrobial use, surveillance, infection control pre-cautions, environmental measures, and decoloniza-tion. Recommendations for each category apply toand are adapted for the various health care settings.
Siegel et al December 2007 S71
Table 2. Clinical syndromes or conditions warranting empiric transmission-based precautions in addition to StandardPrecautions pending confirmation of diagnosis*
Clinical syndrome or conditiony Potential pathogensz
Empiric precautions (always includes
Standard Precautions)
Diarrhea
Acute diarrhea with a likely infectious cause in
an incontinent or diapered patient
Enteric pathogens§ Contact Precautions (pediatrics and adult)
Meningitis Neisseria meningitidis Droplet Precautions for first 24 hours of
antimicrobial therapy; mask and face
protection for intubation
Enteroviruses Contact Precautions for infants and children
Mycobacterium tuberculosis Airborne Precautions if pulmonary infiltrate
present
Airborne Precautions plus Contact Precautions if
potentially infectious draining body fluid
present
Rash or exanthems, generalized, etiology
unknown
Petechial/ecchymotic with fever (general) Neisseria meningitides Droplet Precautions for the first 24 hours of
antimicrobial therapy
Positive history of travel to an area with an
ongoing outbreak of VHF in the 10 days
before onset of fever
Ebola, Lassa, Marburg viruses Droplet Precautions plus Contact Precautions,
Vaccinia virus Contact Precautions only if herpes simplex,
localized zoster in an immunocompetent host,
or vaccinia virus likely
Maculopapular with cough, coryza, and fever Rubeola (measles) virus Airborne Precautions
Respiratory infections
Cough/fever/upper lobe pulmonary infiltrate
in an HIV-negative patient or a patient at
low risk for HIV infection
M. tuberculosis, respiratory viruses, Streptococcus
pneumoniae, Staphylococcus aureus (MSSA or
MRSA)
Airborne Precautions plus Contact Precautions
Cough/fever/pulmonary infiltrate in any lung
location in an HIV-infected patient or a
patient at high risk for HIV infection
M tuberculosis, respiratory viruses, S pneumoniae,
S aureus (MSSA or MRSA)
Airborne Precautions plus Contact Precautions;
eye/face protection if aerosol-generating
procedure performed or contact with
respiratory secretions anticipated; Droplet
Precautions instead of Airborne Precautions if
tuberculosis unlikely and airborne infection
isolation room and/or respirator unavailable
(tuberculosis more likely in HIV-infected than
in HIV-negative individuals)
Cough/fever/pulmonary infiltrate in any lung
location in a patient with a history of recent
travel (10 to 21 days) to countries with
active outbreaks of SARS, avian influenza
M tuberculosis, severe acute respiratory
syndrome virus (SARS-CoV), avian influenza
Airborne plus Contact Precautions plus eye
protection; Droplet Precautions instead of
Airborne Precautions if SARS and tuberculosis
unlikely
Respiratory infections, particularly
bronchiolitis and pneumonia, in infants and
young children
Respiratory syncytial virus, parainfluenza virus,
adenovirus, influenza virus, human
metapneumovirus
Contact plus Droplet Precautions; discontinue
Droplet Precautions if adenovirus and
influenza ruled out
Skin or wound infection
Abscess or draining wound that cannot be
covered
S aureus (MSSA or MRSA), group A
streptococcus
Contact Precautions, plus Droplet Precautions
for the first 24 hours of appropriate
antimicrobial therapy if invasive group A
streptococcal disease suspected
*Infection control professionals should modify or adapt this table according to local conditions. To ensure that appropriate empiric precautions are implemented always, hospitals
must have systems in place to evaluate patients routinely according to these criteria as part of their preadmission and admission care.yPatients with the syndromes or conditions listed below may present with atypical signs or symptoms (eg, neonates and adults with pertussis may not have paroxysmal or severe
cough). The clinician’s index of suspicion should be guided by the prevalence of specific conditions in the community, as well as clinical judgment.zThe organisms listed under the column ‘‘Potential Pathogens’’ are not intended to represent the complete, or even most likely, diagnoses, but rather possible etiologic agents that
require additional precautions beyond Standard Precautions until they can be ruled out.§These pathogens include enterohemorrhagic Escherichia coli O157:H7, Shigella spp, hepatitis A virus, noroviruses, rotavirus, and Clostridium difficile.
S72 Vol. 35 No. 10 Supplement 2 Siegel et al
Table 3. Infection control considerations for high-priority (CDC category A) diseases that may result from bioterroristattacks or are considered bioterrorist threats (see http://www.bt.cdc.gov)
Disease Anthrax
Site(s) of infection; transmission mode Cutaneous (contact with spores); RT (inhalation of spores); GIT (ingestion of spores [rare])
Cutaneous and inhalation disease
have occurred in past bioterrorist
incidents
Comment: Spores can be inhaled into the lower respiratory tract. The infectious dose of Bacillus anthracis in humans by any
route is not precisely known. In primates, the LD50 for an aerosol challenge with B anthracis is estimated to be 8,000 to 50,000
spores; the infectious dose may be as low as 1 to 3 spores.
Incubation period Cutaneous: 1 to 12 days; RT: Usually 1 to 7 days, but up to 43 days reported; GIT: 15 to 72 hours
Clinical features Cutaneous: Painless, reddish papule that develops a central vesicle or bulla in 1 to 2 days; over the next 3 to 7 days, the lesion
becomes pustular and then necrotic, with black eschar and extensive surrounding edema
RT: Initial flu-like illness for 1 to 3 days with headache, fever, malaise, cough; by day 4, severe dyspnea and shock. Usually fatal (85%
to 90%) if untreated; meningitis develops in 50% of RT cases.
GIT: In intestinal form, necrotic, ulcerated edematous lesions develop in intestines with fever, nausea, and vomiting and
progression to hematemesis and bloody diarrhea; 25% to 60% mortality
Diagnosis Cutaneous: Swabs of lesion (under eschar) for IHC, PCR, and culture; punch biopsy for IHC, PCR, and culture; vesicular fluid
aspirate for Gram’s stain and culture; blood culture if systemic symptoms present; acute and convalescent sera for ELISA
serology
RT: CXR or CT demonstrating wide mediastinal widening and/or pleural effusion and hilar abnormalities; blood for culture and
PCR; pleural effusion for culture, PCR, and IHC; CSF (if meningeal signs present) for IHC, PCR, and culture; acute and
convalescent sera for ELISA serology; pleural and/or bronchial biopsy specimens for IHC
GIT: Blood and ascites fluid, stool samples, rectal swabs, and swabs of oropharyngeal lesions, if present, for culture, PCR, and
IHC
Infectivity Cutaneous: Person-to-person transmission from contact with lesion of untreated patient is possible but rare
RT and GIT: Person-to-person transmission does not occur
Aerosolized powder, environmental exposures: Highly infectious if aerosolized
Recommended precautions Cutaneous: Standard Precautions; Contact Precautions if uncontained copious drainage present
clothing; decontamination of persons with powder on them (see http://www.cdc.gov/mmwr/preview/mmwrhtml/
mm5135a3.htm)
Hand hygiene: Handwashing for 30 to 60 seconds with soap and water or 2% chlorhexidene gluconate after spore contact;
alcohol hand rubs are inactive against spores.981
Postexposure prophylaxis after environmental exposure: A 60-day course of antimicrobials (doxycycline, ciprofloxacin,
or levofloxacin) and postexposure vaccine under IND.
Disease Botulism
Site(s) of infection; transmission mode GIT: Ingestion of toxin-containing food; RT: Inhalation of toxin containing aerosol. Comment: Toxin ingested or potentially
delivered by aerosol in bioterrorist incidents. LD50 for type A is 0.001 mg/mL/kg.
Incubation period 1 to 5 days.
Clinical features Ptosis, generalized weakness, dizziness, dry mouth and throat, blurred vision, diplopia, dysarthria, dysphonia, and dysphagia,
followed by symmetrical descending paralysis and respiratory failure.
Diagnosis Clinical diagnosis: identification .of toxin in stool, serology, unless toxin-containing material available for toxin neutralization
bioassays.
Infectivity Not transmitted from person to person; exposure to toxin necessary for disease.
Recommended precautions Standard Precautions.
Disease Ebola Hemorrhagic Fever
Site(s) of infection; transmission mode As a rule, infection develops after exposure of mucous membranes or RT, or through broken skin or percutaneous injury.
Incubation period 2 to 19 days, usually 5 to 10 days
Clinical features Febrile illnesses with malaise, myalgias, headache, vomiting, and diarrhea that are rapidly complicated by hypotension, shock, and
hemorrhagic features. Massive hemorrhage in , 50% of patients.
Diagnosis Etiologic diagnosis can be made using reverse-transcription-PCR, serologic detection of antibody and antigen, pathologic
assessment with immunohistochemistry, and viral culture with electromicroscopic confirmation of morphology,
Infectivity Person-to-person transmission occurs primarily through unprotected contact with blood and body fluids; percutaneous injuries
(eg, needlestick) are associated with a high rate of transmission. Transmission in health care settings has been reported but can
be prevented by use of Barrier Precautions.
Recommended precautions Hemorrhagic fever–specific Barrier Precautions: If disease is believed to be related to intentional release of a bioweapon,
then the epidemiology of transmission is unpredictable pending observation of disease transmission. Until the nature of the
pathogen is understood and its transmission pattern confirmed, Standard, Contact, and Airborne Precautions should be used.
Once the pathogen is characterized, if the epidemiology of transmission is consistent with natural disease, then Droplet
Precautions can be substituted for Airborne Precautions. Emphasize the following: (1) use of sharps safety devices and safe
work practices, (2) proper hand hygiene, (3) barrier protection against blood and body fluids on entry into room (single gloves
and fluid-resistant or impermeable gown, face/eye protection with masks, goggles or face shields), and (4) appropriate waste
handling. Use N95 or higher respirators when performing aerosol-generating procedures. In settings where AIIRs are
unavailable or the large numbers of patients cannot be accommodated by existing AIIRs, observe Droplet Precautions (plus
Standard and Contact Precautions) and segregate patients from those not suspected as having VHF infection. Limit blood draws
to those essential to care. See the text for discussion and Appendix A for recommendations for naturally occurring VHFs.
Site(s) of infection; transmission mode RT: Inhalation of respiratory droplets. Comment: Pneumonic plague is most likely when used as a biological weapon, but some
cases of bubonic and primary septicemia also may occur. Infective dose, 100 to 500 bacteria.
Incubation period 1 to 6 days, usually 2 to 3 days.
Clinical features Pneumonic: Fever, chills, headache, cough, dyspnea, rapid progression of weakness, and, in later stages, hemoptysis, circulatory
collapse, and bleeding diathesis.
Diagnosis Presumptive is diagnosis from Gram’s stain or Wayson’s stain of sputum, blood, or lymph node aspirate; definitive diagnosis is
from cultures of same material or paired acute/convalescent serology.
Infectivity Person-to-person transmission occurs through respiratory droplets. Risk of transmission is low during the first 20 to 24 hours of
illness and requires close contact. Respiratory secretions probably are not infectious within a few hours after initiation of
appropriate therapy.
Recommended precautions Standard and Droplet Precautions until patients have received 48 hours of appropriate therapy. Chemoprophylaxis: Consider
antibiotic prophylaxis for HCWs with close contact exposure.
Disease Smallpox
Site(s) of infection; transmission mode RT Inhalation of droplet or, rarely, aerosols; and skin lesions (contact with virus).
Comment: If used as a biological weapon, natural disease (which has not occurred since 1977) likely will result.
Incubation period 7 to 19 days (mean, 12 days).
Clinical features Fever, malaise, backache, headache, and often vomiting for 2 to 3 days, followed by generalized papular or maculopapular
rash (more on face and extremities), which becomes vesicular (on day 4 or 5) and then pustular; lesions all in same
stage.
Diagnosis Electron microscopy of vesicular fluid or culture of vesicular fluid by a World Health Organization–approved laboratory (CDC);
detection by PCR available only at select LRN laboratories, the CDC, and US Army Medical Research Institute of Infectious
Diseases.
Infectivity Secondary attack rates up to 50% in unvaccinated persons. Infected persons may transmit disease from the time that rash appears
until all lesions have crusted over (about 3 weeks). Infectivity is greatest during the first 10 days of rash.
Recommended precautions Combined use of Standard, Contact, and Airborne Precautions should be maintained until all scabs have separated (3 to 4
weeks).y Only immune HCWs should care for patients. Postexposure vaccine should be provided within 4 days.
Vacciniaz: HCWs to cover vaccination site with gauze and semipermeable dressing until scab separates ($ 21 days). Hand
hygiene should be observed.
Adverse events with virus-containing lesions: Standard Precautions plus Contact Precautions until all lesions are
crusted.
Disease Tularemia
Site(s) of infection; transmission mode RT: Inhalation of aerosolized bacteria; GIT: Ingestion of food or drink contaminated with aerosolized bacteria.
Comment: Pneumonic or typhoidal disease likely to occur after bioterrorist event using aerosol delivery. Infective dose, 10 to
50 bacteria.
Incubation period 2 to 10 days; usually 3 to 5 days.
Clinical features Pneumonic: malaise, cough, sputum production, dyspnea. Typhoidal: fever, prostration, weight loss and frequently an associated
pneumonia.
Diagnosis Diagnosis usually made with serology on acute and convalescent serum specimens; bacterium can be detected by PCR (LRN) or
isolated from blood and other body fluids on cysteine-enriched media or mouse inoculation.
Infectivity Person-to-person spread is rare. Laboratory workers who encounter/handle cultures of this organism are at high risk for disease
*Pneumonic plague is not as contagious as is often thought. Historical accounts and contemporary evidence indicate that persons with plague usually transmit the in-
fection only when the disease is in the end stage. These persons cough copious amounts of bloody sputum that contains many plague bacteria. Patients in the early
stage of primary pneumonic plague (approximately the first 20 to 24 hours) apparently pose little risk (Wu L-T. A treatise on pneumonic plague. Geneva, Switzerland:
League of Nations; 1926; Kool JL. Risk of person-to-person transmission of pneumonic plague. Clin Infect Dis 2005;40:1166-72). Antibiotic medication rapidly clears the
sputum of plague bacilli, so that a patient generally is not infective within hours after initiation of effective antibiotic treatment (Butler TC. Plague and other Yersinia
infections. In: Greenough WB, editor. Current topics in infectious disease. New York: Plenum; 1983). This means that in modern times, many patients will never reach
a stage where they pose a significant risk to others. Even in the end stage of disease, transmission occurs only after close contact. Simple protective measures, such as
wearing masks, maintaining good hygiene, and avoiding close contact, have been effective in interrupting transmission during many pneumonic plague outbreaks; in the
United States, the last known case of person-to-person transmission of pneumonic plague occurred in 1925 (Kool JL. Risk of person-to-person transmission of pneumonic
plague. Clin Infect Dis 2005;40:1166-72).yTransmission by the airborne route is a rare event. Airborne Precautions are recommended when possible, but in the event of mass exposures, Barrier Precautions and con-
tainment within a designated area are most important.204,212
zVaccinia adverse events with lesions containing infectious virus include inadvertent autoinoculation, ocular lesions (blepharitis, conjunctivitis), generalized vaccinia, progressive
vaccinia, and eczema vaccinatum. Bacterial superinfection also requires addition of Contact Precautions if exudates cannot be contained.216, 217
S74 Vol. 35 No. 10 Supplement 2 Siegel et al
Table 4. Recommendations for application of Standard Precautions for the care of all patients in all healthcare settings (seeSections II.D to II.J and III.A.1)
Component Recommendations
Hand hygiene After touching blood, body fluids, secretions, excretions, contaminated
items; immediately after removing gloves; between patient contacts
Personal protective equipment (PPE)
Gloves For touching blood, body fluids, secretions, excretions, contaminated
items, mucous membranes, and nonintact skin
Gown During procedures and patient care activities when contact of clothing/
exposed skin with blood/body fluids, secretions, and excretions is
anticipated
Mask, eye protection (goggles), face shield* During procedures and patient care activities likely to generate splashes or
sprays of blood, body fluids, secretions, especially suctioning,
endotracheal intubation
Soiled patient care equipment Handle in a manner that prevents transfer of microorganisms to others and
to the environment; wear gloves if visibly contaminated; perform hand
hygiene
Environmental control Develop procedures for routine care, cleaning, and disinfection of
environmental surfaces, especially frequently touched surfaces in patient
care areas
Textiles and laundry Handle in a manner that prevents transfer of microorganisms to others and
to the environment
Needles and other sharps Do not recap, bend, break, or hand-manipulate used needles; if recapping is
required, use a one-handed scoop technique only; use safety features
when available; place used sharps in puncture-resistant container
Patient resuscitation Use mouthpiece, resuscitation bag, other ventilation devices to prevent
contact with mouth and oral secretions
Patient placement Prioritize for single-patient room if patient is at increased risk of
transmission, is likely to contaminate the environment, does not maintain
appropriate hygiene, or is at increased risk of acquiring infection or
developing adverse outcome after infection
Respiratory hygiene/cough etiquette (source containment of infectious
respiratory secretions in symptomatic patients, beginning at initial point
of encounter, eg, triage and reception areas in emergency departments
and physician offices)
Instruct symptomatic persons to cover mouth/nose when sneezing/
coughing; use tissues and dispose in no-touch receptacle; observe
hand hygiene after soiling of hands with respiratory secretions; wear
surgical mask if tolerated or maintain spatial separation, .3 feet if
possible.
*During aerosol-generating procedures on patients with suspected or proven infections transmitted by respiratory aerosols (eg, severe acute respiratory syndrome), wear a fit-
tested N95 or higher respirator in addition to gloves, gown, and face/eye protection.
With the increasing incidence and prevalence ofMDROs, all health care facilities must prioritize effec-tive control of MDRO transmission. Facilities shouldidentify prevalent MDROs at the facility, implementcontrol measures, assess the effectiveness of controlprograms, and demonstrate decreasing MDRO rates.A set of intensified MDRO prevention interventionsis to be added if the incidence of transmission ofa target MDRO is not decreasing despite implemen-tation of basic MDRO infection control measures,and when the first case of an epidemiologically
important MDRO is identified within a health carefacility.
SUMMARY
This updated guideline responds to changes in healthcare deliveryand addresses newconcerns about transmis-sion of infectious agents to patients and HCWs in theUnited States and infection control. The primary objectiveof the guideline is to improve the safety of the nation’shealth care delivery system by reducing the rates of HAIs.
Siegel et al December 2007 S75
Table 5. Components of a protective environment
I. Patients: allogeneic hematopoeitic stem cell transplantation only
d Maintain in protective environment (PE) room except for required diagnostic or therapeutic procedures that cannot be performed in the room (eg,
radiology, surgery)
d Respiratory protection (eg, N95 respirator) for the patient when leaving PE during periods of construction
II. Standard and Expanded Precautions
d Hand hygiene observed before and after patient contact
d Gown, gloves, mask not required for health care workers (HCWs) or visitors for routine entry into the room
d Use of gown, gloves, and mask by HCWs and visitors according to Standard Precautions and as indicated for suspected or proven infections for which
transmission-based precautions are recommended
III. Engineering
d Central or point-of-use high-efficiency particulate air (HEPA) filters (99.97% efficiency) filters capable of removing particles 0.3 mm in diameter in supply
(incoming) air
d Well-sealed rooms:
- Proper construction of windows, doors, and intake and exhaust ports
- Ceilings: smooth, free of fissures, open joints, crevices
- Walls sealed above and below the ceiling
- If leakage detected, locate source and make necessary repairs
d Ventilation to maintain $12 air changes/hour
d Directed air flow; air supply and exhaust grills located so that clean, filtered air enters from one side of the room, flows across the patient’s bed, and exits
on opposite side of the room
d Positive room air pressure in relation to the corridor; pressure differential of .2.5 Pa (0.01-inch water gauge)
d Air flow patterns monitored and recorded daily using visual methods (eg, flutter strips, smoke tubes) or a hand-held pressure gauge
d Self-closing door on all room exits
d Back-up ventilation equipment (eg, portable units for fans or filters) maintained for emergency provision of ventilation requirements for PE areas, with
immediate steps taken to restore the fixed ventilation system
d For patients who require both a PE and an airborne infection isolation room (AIIR), use an anteroom to ensure proper air balance relationships and
provide independent exhaust of contaminated air to the outside, or place a HEPA filter in the exhaust duct. If an anteroom is not available, place patient in
an AIIR and use portable ventilation units, industrial-grade HEPA filters to enhance filtration of spores.
IV. Surfaces
d Daily wet-dusting of horizontal surfaces using cloths moistened with EPA-registered hospital disinfectant/detergent
d Avoid dusting methods that disperse dust
d No carpeting in patient rooms or hallways
d No upholstered furniture and furnishings
V. Other
d No flowers (fresh or dried) or potted plants in PE rooms or areas
d Vacuum cleaner equipped with HEPA filters when vacuum cleaning is necessary
Adapted from Centers for Disease Control and Prevention.11
ABBREVIATIONS USED IN THE GUIDELINE
AIA American Institute of ArchitectsAIIR Airborne infection isolation roomCDC Centers for Disease Control and PreventionCF Cystic fibrosisCJD Creutzfeld-Jakob DiseaseESBL Extended-spectrum beta-lactamaseFDA Food and Drug AdministrationHAI Health care–associated infectionHBV Hepatitis B virusHCV Hepatitis C virusHEPA High-efficiency particulate airHICPAC Health Care Infection Control Practices Advi-
sory CommitteeHIV Human immunodeficiency virusHCW Health care workerHFV Hemorrhagic fever virusHSCT Hematopoetic stem cell transplantation
ICP Infection prevention and controlprofessional
ICU Intensive care unitLTCF Long-term care facilityMDR-GNB Multidrug-resistant gram-negative bacilliMDRO Multidrug-resistant organismMRSA Methicillin-resistant Staphylococcus aureusMSSA Methicillin-susceptible Staphylococcus
aureusNICU Neonatal intensive care unitNIOSH National Institute for Occupational Safety
and HealthNNIS National Nosocomial Infection SurveillanceNSSP Nonsusceptible Streptococcus pneumoniaeOSHA Occupational Safety and Health
AdministrationPCR Polymerase chain reactionPE Protective environmentPFGE Pulsed-field gel electrophoresisPICU Pediatric intensive care unit
S76 Vol. 35 No. 10 Supplement 2 Siegel et al
PPE Personal protective equipmentRSV Respiratory syncytial virusSARS Severe acute respiratory syndromevCJD variant Creutzfeld-Jakob diseaseVISA Vancomycin-intermediate/resistannt Staphy-
lococcus aureusVRE Vancomycin-resistant enterococciVRSA Vancomycin-resistant Staphylococcus aureusWHO World Health Organization
PART I: REVIEW OF SCIENTIFIC DATAREGARDING TRANSMISSION OF INFECTIOUSAGENTS IN HEALTH CARE SETTINGS
I.A. Evolution of the 2007 Document
The Guideline for Isolation Precautions: PreventingTransmission of Infectious Agents in Health care Set-tings 2007 builds on a series of isolation and infectionprevention documents promulgated since 1970. Theseprevious documents are summarized and referenced inTable 1 and in Part I of the 1996 Guideline for IsolationPrecautions in Hospitals.1
I.A.1. Objectives and Methods. The objectives ofthis guideline are to (1) provide infection control recom-mendations for all components of the health caredelivery system, including hospitals, long-term carefacilities, ambulatory care, home care, and hospice; (2)reaffirm Standard Precautions as the foundation for pre-venting transmission during patient care in all healthcare settings; (3) reaffirm the importance of implement-ing Transmission-Based Precautions based on the clini-cal presentation or syndrome and likely pathogens untilthe infectious etiology has been determined (Table 2);and (4) provide epidemiologically sound and, wheneverpossible, evidence-based recommendations.
This guideline is designed for use by individualswho are charged with administering infection controlprograms in hospitals and other health care settings.The information also will be useful for other HCWs,health care administrators, and anyone needing infor-mation about infection control measures to preventtransmission of infectious agents. Commonly used ab-breviations are provided, and terms used in the guide-line are defined in the Glossary.
Medline and PubMed were used to search for rele-vant studies published in English, focusing on thosepublished since 1996. Much of the evidence cited forpreventing transmission of infectious agents in healthcare settings is derived from studies that used ‘‘quasi-experimental designs,’’ also referred to as nonrandom-ized preintervention and postintervention studydesigns.2 Although these types of studies can providevaluable information regarding the effectiveness ofvarious interventions, several factors decrease the cer-tainty of attributing improved outcome to a specific
intervention. These include: difficulties in controllingfor important confounding variables, the use of multi-ple interventions during an outbreak, and results thatare explained by the statistical principle of regressionto the mean (eg, improvement over time without anyintervention).3 Observational studies remain relevantand have been used to evaluate infection control inter-ventions.4,5 The quality of studies, consistency of re-sults, and correlation with results from randomizedcontrolled trials, when available, were considered dur-ing the literature review and assignment of evidence-based categories (see Part IV: Recommendations) tothe recommendations in this guideline. Several authorshave summarized properties to consider when evaluat-ing studies for the purpose of determining whether theresults should change practice or in designing newstudies.2,6,7
I.A.2. Changes or Clarifications in Terminology.This guideline contains 4 changes in terminologyfrom the 1996 guideline:
1. The term ‘‘nosocomial infection’’ is retained to referonly to infections acquired in hospitals. The term‘‘health care–associated infection’’ (HAI) is used torefer to infections associated with health care deliv-ery in any setting (eg, hospitals, long-term care facil-ities, ambulatory settings, home care). This termreflects the inability to determine with certaintywhere the pathogen was acquired, because patientsmay be colonized with or exposed to potential path-ogens outside of the health care setting before re-ceiving health care, or may develop infectionscaused by those pathogens when exposed to theconditions associated with delivery of health care.In addition, patients frequently move among thevarious settings within the health care system.8
2. A new addition to the practice recommendations forStandard Precautions is respiratory hygiene/coughetiquette. Whereas Standard Precautions generallyapply to the recommended practices of HCWs dur-ing patient care, respiratory hygiene/cough etiquetteapplies broadly to all persons who enter a healthcare setting, including HCWs, patients, and visitors.These recommendations evolved from observationsduring the SARS epidemic that failure to implementbasic source control measures with patients, visitors,and HCWs with signs and symptoms of respiratorytract infection may have contributed to SARS-CoVtransmission. This concept has been incorporatedinto CDC planning documents for SARS and pan-demic influenza.9,10
3. The term ‘‘Airborne Precautions’’ has been supple-mented by the term ‘‘Airborne Infection IsolationRoom’’ (AIIR), to achieve consistency with theGuidelines for Environmental Infection Control in
Siegel et al December 2007 S77
Health Care Facilities,11 the Guidelines for Preventingthe Transmission of Mycobacterium tuberculosis inHealth Care Settings 2005,12 and the American Insti-tute of Architects (AIA) 2006 guidelines for designand construction of hospitals.13
4. A set of prevention measures known as the protec-tive environment (PE) has been added to the precau-tions for preventing HAIs. These measures, whichhave been defined in previous guidelines, consistof engineering and design interventions aimed atdecreasing the risk of exposure to environmentalfungi for severely immunocompromised patientsundergoing allogeneic HSCT during the times ofhighest risk, usually the first 100 days posttrans-plantation or longer in the presence of graft-ver-sus-host disease.11,13-15 Recommendations for a PEapply only to acute care hospitals that providecare to patients undergoing HSCT.
I.A.3. Scope. This guideline, like its predecessors, fo-cuses primarily on interactions between patients andhealth care providers. The Guidelines for the Preventionof MDRO Infection were published separately in Novem-ber 2006 and are available online at http://www.cdc.gov/ncidod/dhqp/index.html. Several other HICPACguidelines to prevent transmission of infectious agentsassociated with health care delivery are cited, includingGuideline for Hand Hygiene, Guideline for EnvironmentalInfection Control, Guideline for Prevention of HealthCare–Associated Pneumonia, and Guideline for InfectionControl in Health Care Personnel.11,14,16,17 In combina-tion, these provide comprehensive guidance on the pri-mary infection control measures for ensuring a safeenvironment for patients and HCWs.
This guideline does not discuss in detail specializedinfection control issues in defined populations that areaddressed elsewhere (eg, Recommendations for Pre-venting Transmission of Infections Among Chronic He-modialysis Patients, Guidelines for Preventing theTransmission of Mycobacterium tuberculosis in HealthCare Facilities 2005, Guidelines for Infection Control inDental Health Care Settings, and Infection Control Rec-ommendations for Patients With Cystic Fibrosis.12,18-20
An exception has been made by including abbreviatedguidance for a PE used for allogeneic HSCT recipients,because components of the PE have been definedmore completely since publication of the Guidelinesfor Preventing Opportunistic Infections Among HSCTRecipients in 2000 and the Guideline for EnvironmentalInfection Control in Health Care Facilities.11,15
I.B. Rationale for Standard and Transmission-Based Precautions in Health Care Settings
Transmission of infectious agents within a healthcare setting requires 3 elements: a source (or reservoir)
of infectious agents, a susceptible host with a portal ofentry receptive to the agent, and a mode of transmis-sion for the agent. This section describes the interrela-tionship of these elements in the epidemiology of HAIs.
I.B.1. Sources of Infectious Agents. Infectiousagents transmitted during health care derive primarilyfrom human sources but inanimate environmentalsources also are implicated in transmission. Human res-ervoirs include patients,20-28 HCWs,17,29-39 and house-hold members and other visitors.40-45 Such sourceindividuals may have active infections, may be in theasymptomatic and/or incubation period of an infectiousdisease, or may be transiently or chronically colonizedwith pathogenic microorganisms, particularly in therespiratory and gastrointestinal tracts. Other sourcesof HAIs are the endogenous flora of patients (eg, bacteriaresiding in the respiratory or gastrointestinal tract).46-54
I.B.2. Susceptible Hosts. Infection is the result of acomplex interrelationship between a potential hostand an infectious agent. Most of the factors that influ-ence infection and the occurrence and severity of dis-ease are related to the host. However, characteristicsof the host–agent interaction as it relates to pathoge-nicity, virulence, and antigenicity also are important,as are the infectious dose, mechanisms of disease pro-duction, and route of exposure.55 There is a spectrumof possible outcomes after exposure to an infectiousagent. Some persons exposed to pathogenic microor-ganisms never develop symptomatic disease, whereasothers become severely ill and even die. Some individ-uals are prone to becoming transiently or permanentlycolonized but remain asymptomatic. Still others pro-gress from colonization to symptomatic disease eitherimmediately after exposure or after a period of asymp-tomatic colonization. The immune state at the time ofexposure to an infectious agent, interaction betweenpathogens, and virulence factors intrinsic to the agentare important predictors of an individual’s outcome.Host factors such as extremes of age and underlyingdisease (eg, diabetes56,57, human immunodeficiencyvirus/acquired immune deficiency syndrome [HIV/AIDS],58,59 malignancy, and transplantation18,60,61)can increase susceptibility to infection, as can variousmedications that alter the normal flora (eg, antimicro-bial agents, gastric acid suppressors, corticosteroids,antirejection drugs, antineoplastic agents, immunosup-pressive drugs). Surgical procedures and radiation ther-apy impair defenses of the skin and other involvedorgan systems. Indwelling devices, such as urinarycatheters, endotracheal tubes, central venous and arte-rial catheters,62-64 and synthetic implants, facilitate de-velopment of HAIs by allowing potential pathogensto bypass local defenses that ordinarily would impedetheir invasion and by providing surfaces for develop-ment of biofilms that may facilitate adherence of
microorganisms and protect from antimicrobial activ-ity.65 Some infections associated with invasive proce-dures result from transmission within the health carefacility; others arise from the patient’s endogenousflora.46-50 High-risk patient populations with notewor-thy risk factors for infection are discussed further inSections I.D, I.E, and I.F.
I.B.3. Modes of Transmission. Several classes ofpathogens can cause infection, including bacteria, vi-ruses, fungi, parasites, and prions. The modes of trans-mission vary by type of organism, and some infectiousagents may be transmitted by more than 1 route. Someare transmitted primarily by direct or indirect contact,(eg, herpes simplex virus [HSV], respiratory syncytialvirus, S aureus), others by the droplet, (eg, influenzavirus, Bordetella pertussis) or airborne routes (eg, Myco-bacterium tuberculosis). Other infectious agents, suchas bloodborne viruses (eg, hepatitis B virus [HBV], hep-atitis C virus [HCV], HIV), are rarely transmitted inhealth care settings through percutaneous or mucousmembrane exposure. Importantly, not all infectiousagents are transmitted from person to person; theseare listed in Appendix A. The 3 principal routes oftransmission—contact, droplet, and airborne—aresummarized below.
I.B.3.a. Contact Transmission. The most commonmode of transmission, contact transmission is dividedinto 2 subgroups: direct contact and indirect contact.
I.B.3.a.i. Direct Contact Transmission. Directtransmission occurs when microorganisms are trans-ferred from an infected person to another person with-out a contaminated intermediate object or person.Opportunities for direct contact transmission betweenpatients and HCWs have been summarized in HICPAC’sGuideline for Infection Control in Health Care Personnel,199817 and include the following:
d Blood or other blood-containing body fluids from apatient directly enters a HCW’s body through contactwith a mucous membrane66 or breaks (ie, cuts, abra-sions) in the skin.67
d Mites from a scabies-infested patient are transferredto a HCW’s skin while he or she is in direct unglovedcontact with the patient’s skin.68,69
d A HCW develops herpetic whitlow on a finger aftercontact with HSV when providing oral care to a pa-tient without using gloves, or HSV is transmitted toa patient from a herpetic whitlow on an unglovedhand of a HCW.70,71
I.B.3.a.ii. Indirect Contact Transmission. Indirecttransmission involves the transfer of an infectiousagent through a contaminated intermediate object orperson. In the absence of a point-source outbreak, itis difficult to determine how indirect transmission oc-curs. However, extensive evidence cited in the Guideline
for Hand Hygiene in Health Care Settings suggests thatthe contaminated hands of HCWs are important con-tributors to indirect contact transmission.16 Examplesof opportunities for indirect contact transmission in-clude the following:
d A HCWs’ hands may transmit pathogens after touch-ing an infected or colonized body site on 1 patient ora contaminated inanimate object, if hand hygiene isnot performed before touching another patient.72,73
d Patient-care devices (eg, electronic thermometers,glucose monitoring devices) may transmit pathogensif devices contaminated with blood or body fluids areshared between patients without cleaning and disin-fecting between patients.74-77
d Shared toys may become a vehicle for transmittingrespiratory viruses (eg, respiratory syncytial virus[RSV]24,78,79 or pathogenic bacteria (eg, Pseudomonasaeruginosa80) among pediatric patients.
d Instruments that are inadequately cleaned betweenpatients before disinfection or sterilization (eg, endo-scopes or surgical instruments)81-85 or that havemanufacturing defects that interfere with the effec-tiveness of reprocessing86,87 may transmit bacterialand viral pathogens.
Clothing, uniforms, laboratory coats, or isolationgowns used as PPE may become contaminated withpotential pathogens after care of a patient colonizedor infected with an infectious agent, (eg, MRSA,88 van-comycin-resistant enterococci [VRE],89 and C diffi-cile90). Although contaminated clothing has not beenimplicated directly in transmission, the potential existsfor soiled garments to transfer infectious agents to suc-cessive patients.
I.B.3.b. Droplet Transmission. Droplet transmis-sion is technically a form of contact transmission;some infectious agents transmitted by the droplet routealso may be transmitted by direct and indirect contactroutes. However, in contrast to contact transmission,respiratory droplets carrying infectious pathogenstransmit infection when they travel directly from therespiratory tract of the infectious individual to suscep-tible mucosal surfaces of the recipient, generally overshort distances, necessitating facial protection. Respi-ratory droplets are generated when an infected personcoughs, sneezes, or talks91,92 or during such proce-dures as suctioning, endotracheal intubation,93-96
cough induction by chest physiotherapy,97 and cardio-pulmonary resuscitation.98,99 Evidence for droplettransmission comes from epidemiologic studies of dis-ease outbreaks,100-103 from experimental studies,104
and from information on aerosol dynamics.91,105 Stud-ies have shown that the nasal mucosa, conjunctivae,and, less frequently, the mouth are susceptible portalsof entry for respiratory viruses.106 The maximum
Siegel et al December 2007 S79
distance for droplet transmission is currently unre-solved; pathogens transmitted by the droplet routehave not been transmitted through the air over longdistances, in contrast to the airborne pathogens dis-cussed below. Historically, the area of defined risk hasbeen a distance of , 3 feet around the patient, basedon epidemiologic and simulated studies of selected in-fections.103,104 Using this distance for donning maskshas been effective in preventing transmission of infec-tious agents through the droplet route. However, exper-imental studies with smallpox107,108 and investigationsduring the global SARS outbreaks of 2003101 suggestthat droplets from patients with these 2 infectionscould reach persons located 6 feet or more from theirsource. It is likely that the distance that droplets traveldepends on the velocity and mechanism by which res-piratory droplets are propelled from the source, thedensity of respiratory secretions, environmental fac-tors (eg, temperature, humidity), and the pathogen’sability to maintain infectivity over that distance.105
Thus, a distance of , 3 feet around the patient is bestconsidered an example of what is meant by ‘‘a shortdistance from a patient’’ and should not be used asthe sole criterion for determining when a mask shouldbe donned to protect from droplet exposure. Based onthese considerations, it may be prudent to don a maskwhen within 6 to 10 feet of the patient or on entry intothe patient’s room, especially when exposure toemerging or highly virulent pathogens is likely. Morestudies are needed to gain more insight into droplettransmission under various circumstances.
Droplet size is another variable under investigation.Droplets traditionally have been defined as being . 5mm in size. Droplet nuclei (ie, particles arising from des-iccation of suspended droplets) have been associatedwith airborne transmission and defined as , 5 mm insize,105 a reflection of the pathogenesis of pulmonary tu-berculosis that is not generalizeable to other organisms.Observations of particle dynamics have demonstratedthat a range of droplet sizes, including those of diameter$ 30 mm, can remain suspended in the air.109 The be-havior of droplets and droplet nuclei affect recommen-dations for preventing transmission. Whereas fineairborne particles containing pathogens that are ableto remain infective may transmit infections over longdistances, requiring AIIR to prevent its disseminationwithin a facility; organisms transmitted by the dropletroute do not remain infective over long distances andthus do not require special air handling and ventilation.Examples of infectious agents transmitted through thedroplet route include B pertussis,110 influenza virus,23
adenovirus,111 rhinovirus,104 Mycoplasma pneumo-niae,112 SARS-CoV,21,96,113 group A streptococcus,114
and Neisseria meningitides.95,103,115 Although RSV maybe transmitted by the droplet route, direct contact with
infected respiratory secretions is the most important de-terminant of transmission and consistent adherence toStandard Precautions plus Contact Precautions preventstransmission in health care settings.24,116,117
Rarely, pathogens that are not transmitted routinelyby the droplet route are dispersed into the air overshort distances. For example, although S aureus istransmitted most frequently by the contact route, viralupper respiratory tract infection has been associatedwith increased dispersal of S aureus from the noseinto the air for a distance of 4 feet under both outbreakand experimental conditions; this is known as the‘‘cloud baby’’ and ‘‘cloud adult’’ phenomenon.118-120
I.B.3.c. Airborne Transmission. Airborne transmis-sion occurs by dissemination of either airborne dropletnuclei or small particles in the respirable size rangecontaining infectious agents that remain infectiveover time and distance (eg, spores of Aspergillus sppand M tuberculosis). Microorganisms carried in thismanner may be dispersed over long distances by aircurrents and may be inhaled by susceptible individualswho have not had face-to-face contact with (or evenbeen in the same room with) the infectious individ-ual.121-124 Preventing the spread of pathogens thatare transmitted by the airborne route requires the useof special air handling and ventilation systems (eg,AIIRs) to contain and then safely remove the infectiousagent.11,12 Infectious agents to which this applies in-clude M tuberculosis,124-127 rubeola virus (measles),122
and varicella-zoster virus (chickenpox).123 In addition,published data suggest the possibility that variola virus(smallpox) may be transmitted over long distancesthrough the air under unusual circumstances, andAIIRs are recommended for this agent as well; however,droplet and contact routes are the more frequent routesof transmission for smallpox.108,128,129 In addition toAIIRs, respiratory protection with a National Institutefor Occupational Safety and Health (NIOSH)-certifiedN95 or higher-level respirator is recommended forHCWs entering the AIIR, to prevent acquisition ofairborne infectious agents such as M tuberculosis.12
For certain other respiratory infectious agents, suchas influenza130,131 and rhinovirus,104 and even somegastrointestinal viruses (eg, norovirus132 and rotavi-rus133), there is some evidence that the pathogenmay be transmitted through small-particle aerosols un-der natural and experimental conditions. Such trans-mission has occurred over distances . 3 feet butwithin a defined air space (eg, patient room), suggest-ing that it is unlikely that these agents remain viableon air currents that travel long distances. AIIRs arenot routinely required to prevent transmission of theseagents. Additional issues concerning small-particle aer-osol transmission of agents that are most frequentlytransmitted by the droplet route are discussed below.
S80 Vol. 35 No. 10 Supplement 2 Siegel et al
I.B.3.d. Emerging Issues Concerning AirborneTransmission of Infectious Agents.
I.B.3.d.i. Transmission From Patients. The emer-gence of SARS in 2002, the importation of monkeypoxinto the United States in 2003, and the emergence ofavian influenza present challenges to the assignmentof isolation categories due to conflicting informationand uncertainty about possible routes of transmission.Although SARS-CoV is transmitted primarily by contactand/or droplet routes, airborne transmission over a lim-ited distance (eg, within a room) has been suggested, al-though not proven.134-141 This is true of other infectiousagents as well, such as influenza virus130 and norovi-ruses.132,142,143 Influenza viruses are transmitted pri-marily by close contact with respiratory droplets,23,102
and acquisition by HCWs has been prevented by Drop-let Precautions, even when positive-pressure roomswere used in one center.144 However, inhalational trans-mission could not be excluded in an outbreak of influ-enza in the passengers and crew of an aircraft.130
Observations of a protective effect of ultraviolet lightin preventing influenza among patients with tuberculo-sis during the influenza pandemic of 1957–1958 havebeen used to suggest airborne transmission.145,146
In contrast to the strict interpretation of an airborneroute for transmission (ie, long distances beyond the pa-tient room environment), short-distance transmissionby small-particle aerosols generated under specific cir-cumstances (eg, during endotracheal intubation) to per-sons in the immediate area near the patient also has beendemonstrated. Aerosolized particles , 100 mm in diam-eter can remain suspended in air when room air currentvelocities exceed the terminal settling velocities of theparticles.109 SARS-CoV transmission has been associatedwith endotracheal intubation, noninvasive positivepressure ventilation, and cardiopulmonary resuscita-tion.93,94,96,98,141 Although the most frequent routes oftransmission of noroviruses are contact and foodborneand waterborne routes, several reports suggest that nor-oviruses also may be transmitted through aerosolizationof infectious particles from vomitus or fecal mate-rial.142,143,147,148 It is hypothesized that the aerosolizedparticles are inhaled and subsequently swallowed.
Roy and Milton have proposed a new classificationfor aerosol transmission when evaluating routes ofSARS transmission:
d Obligate. Under natural conditions, disease occurs af-ter transmission of the agent only through inhalationof small-particle aerosols (eg, tuberculosis).
d Preferential. Natural infection results from transmis-sion through multiple routes, but small-particle aero-sols are the predominant route (eg, measles, varicella).
d Opportunistic. Under special circumstances, agentsthat naturally cause disease through other routes
may be transmitted through small-particleaerosols.149
This conceptual framework can explain rare occur-rences of airborne transmission of agents that aretransmitted most frequently by other routes (eg, small-pox, SARS, influenza, noroviruses). Concerns about un-known or possible routes of transmission of agentsassociated with severe disease and no known treat-ment often result in the adoption of overextreme pre-vention strategies, and recommended precautionsmay change as the epidemiology of an emerging infec-tion becomes more well defined and controversial is-sues are resolved.
I.B.3.d.ii. Transmission From the Environment.Some airborne infectious agents are derived from theenvironment and do not usually involve person-to-per-son transmission; for example, anthrax spores presentin a finely milled powdered preparation can be aerosol-ized from contaminated environmental surfaces andinhaled into the respiratory tract.150,151 Spores of envi-ronmental fungi (eg, Aspergillus spp) are ubiquitous inthe environment and may cause disease in immuno-compromised patients who inhale aerosolized spores(through, eg, construction dust).152,153 As a rule, nei-ther of these organisms is subsequently transmittedfrom infected patients; however, there is 1 well-docu-mented report of person-to-person transmission ofAspergillus sp in the ICU setting that was most likelydue to the aerosolization of spores during wounddebridement.154 The PE involves isolation practices de-signed to decrease the risk of exposure to environmentalfungal agents in allogeneic HSCT patients.11,14,15,155-158
Environmental sources of respiratory pathogens (eg,Legionella) transmitted to humans through a commonaerosol source is distinct from direct patient-to-patienttransmission.
I.B.3.e. Other Sources of Infection. Sources of in-fection transmission other than infectious individualsinclude those associated with common environmentalsources or vehicles (eg, contaminated food, water, ormedications, such as intravenous fluids). Although As-pergillus spp have been recovered from hospital watersystems,159 the role of water as a reservoir for immuno-suppressed patients remains unclear. Vectorbornetransmission of infectious agents from mosquitoes,flies, rats, and other vermin also can occur in healthcare settings. Prevention of vectorborne transmissionis not addressed in this document.
I.C. Infectious Agents of Special InfectionControl Interest for Health Care Settings
This section discusses several infectious agents withimportant infection control implications that eitherwere not discussed extensively in previous isolation
Siegel et al December 2007 S81
guidelines or have emerged only recently. Included areepidemiologically important organisms (eg, C difficile),agents of bioterrorism, prions, SARS-CoV, monkeypox,noroviruses, and the hemorrhagic fever viruses (HFVs).Experience with these agents has broadened the un-derstanding of modes of transmission and effectivepreventive measures. These agents are included for in-formation purposes and, for some (ie, SARS-CoV, mon-keypox), to highlight the lessons that have beenlearned about preparedness planning and respondingeffectively to new infectious agents.
I.C.1. Epidemiologically Important Organisms. Un-der defined conditions, any infectious agent transmit-ted in a health care setting may become targeted forcontrol because it is epidemiologically important. C dif-ficile is specifically discussed below because of its cur-rent prevalence and seriousness in US health carefacilities. In determining what constitutes an ‘‘epidemi-ologically important organism,’’ the following criteriaapply:
d A propensity for transmission within health care fa-cilities based on published reports and the occur-rence of temporal or geographic clusters of morethan 2 patients, (eg, C difficile, norovirus, RSV, influ-enza, rotavirus, Enterobacter spp, Serratia spp, groupA streptococcus). A single case of health care–associ-ated invasive disease caused by certain pathogens(eg, group A streptococcus postoperatively,160 in aburn unit,161 or in a LTCF;162 Legionella spp,14,163 As-pergillus spp164) is generally considered a trigger forinvestigation and enhanced control measures be-cause of the risk of additional cases and the severityof illness associated with these infections. Antimicro-bial resistance can have the following characteristics:
d Resistance to first-line therapies (eg, MRSA,vancomycin-intermediate/resistannt S aureus [VISA],vancomycin-resistant S aureus [VRSA], VRE, ex-tended-spectrum beta-lactamase [ESBL]-producingorganisms)
d Common and uncommon microorganisms with un-usual patterns of resistance within a facility (eg, thefirst isolate of Burkholderia cepacia complex or Ral-stonia spp in non-CF patients or a quinolone-resis-tant strain of P aeruginosa in a facility)
d Difficult to treat because of innate or acquired resis-tance to multiple classes of antimicrobial agents (eg,Stenotrophomonas maltophilia, Acinetobacter spp)
d Association with serious clinical disease, and in-creased morbidity and mortality (eg, MRSA andmethicillin-susceptible S aureus [MSSA], group Astreptococcus)
d A newly discovered or reemerging pathogen.
I.C.1.a. Clostridium difficile. C difficile is a spore-forming gram-positive anaerobic bacillus that was first
isolated from stools of neonates in 1935165 and identi-fied as the most frequent causative agent of antibiotic-associated diarrhea and pseudomembranous colitis in1977.166 This pathogen is a major cause of healthcare–associated diarrhea and has been responsiblefor many large outbreaks in health care settings thathave proven extremely difficult to control. Importantfactors contributing to health care–associated out-breaks include environmental contamination, persis-tence of spores for prolonged periods, resistance ofspores to routinely used disinfectants and antiseptics,hand carriage by HCWs to other patients, and exposureof patients to frequent courses of antimicrobialagents.167 Antimicrobials most frequently associatedwith increased risk of C difficile include third-genera-tion cephalosporins, clindamycin, vancomycin, andfluoroquinolones.
Since 2001, outbreaks and sporadic cases of C dif-ficile with increased morbidity and mortality haveoccurred in several US states, Canada, England, andthe Netherlands.168-172 The same strain of C difficilehas been implicated in all of these outbreaks;173
this strain, toxinotype III, North American pulsed-field gel electrophoresis (PFGE) type 1, and polymer-ase chain reaction (PCR)-ribotype 027 (NAP1/027),has been found to hyperproduce toxin A (a 16-foldincrease) and toxin B (a 23-fold increase) comparedwith isolates from 12 other PFGE types. A recent sur-vey of US infectious disease physicians found that40% of the respondents perceived recent increasesin the incidence and severity of C difficile disease.174
Standardization of testing methodology and surveil-lance definitions is needed for accurate comparisonsof trends in rates among hospitals.175 It is hypothe-sized that the incidence of disease and apparentheightened transmissibility of this new strain maybe due, at least in part, to the greater productionof toxins A and B, increasing the severity of diarrheaand producing more environmental contamination.Considering the greater morbidity, mortality, lengthof stay, and costs associated with C difficile diseasein both acute care and long-term care facilities,control of this pathogen is becoming increasinglyimportant.
Prevention of transmission focuses on syndromicapplication of Contact Precautions for patients with di-arrhea, accurate identification of affected patients, en-vironmental measures (eg, rigorous cleaning of patientrooms), and consistent hand hygiene. Using soap andwater rather than alcohol-based handrubs for mechan-ical removal of spores from hands and using a bleach-containing disinfectant (5000 ppm) for environmentaldisinfection may be valuable in cases of transmissionin health care facilities. Appendix A provides forrecommendations.
S82 Vol. 35 No. 10 Supplement 2 Siegel et al
I.C.1.b. Multidrug-Resistant Organisms. In gen-eral, MDROs are defined as microorganisms—predomi-nantly bacteria—that are resistant to 1 or more classesof antimicrobial agents.176 Although the names of cer-tain MDROs suggest resistance to only a single agent(eg, MRSA, VRE), these pathogens are usually resistantto all but a few commercially available antimicrobialagents. This latter feature defines MDROs that are con-sidered to be epidemiologically important and deservespecial attention in health care facilities.177 OtherMDROs of current concern include multidrug-resistantStreptococcus pneumoniae, which is resistant to penicil-lin and other broad-spectrum agents such as macrolidesand fluroquinolones, multidrug-resistant gram-nega-tive bacilli (MDR-GNB), especially those producingESBLs; and strains of S aureus that are intermediate orresistant to vancomycin (ie, VISA and VRSA).178-198
MDROs are transmitted by the same routes as anti-microbial susceptible infectious agents. Patient-to-pa-tient transmission in health care settings, usually viahands of HCWs, has been a major factor accountingfor the increase in MDRO incidence and prevalence, es-pecially for MRSA and VRE in acute care facilities.199-
201 Preventing the emergence and transmission ofthese pathogens requires a comprehensive approachthat includes administrative involvement and mea-sures (eg, nurse staffing, communication systems, per-formance improvement processes to ensure adherenceto recommended infection control measures), educa-tion and training of medical and other HCWs, judiciousantibiotic use, comprehensive surveillance for targetedMDROs, application of infection control precautionsduring patient care, environmental measures (eg,cleaning and disinfection of the patient care environ-ment and equipment, dedicated single-patient use ofnoncritical equipment), and decolonization therapywhen appropriate.
The prevention and control of MDROs is a nationalpriority, one that requires that all health care facilitiesand agencies assume responsibility and participate incommunity-wide control programs.176,177 A detaileddiscussion of this topic and recommendations for pre-vention published in 2006 is available at http://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline2006.pdf.
I.C.2. Agents of Bioterrorism. The CDC has desig-nated the agents that cause anthrax, smallpox, plague,tularemia, viral hemorrhagic fevers, and botulism ascategory A (high priority), because these agents canbe easily disseminated environmentally and/or trans-mitted from person to person, can cause high mortalityand have the potential for major public health impact,might cause public panic and social disruption, andnecessitate special action for public health prepared-ness.202 General information relevant to infection
control in health care settings for Category A agentsof bioterrorism is summarized in Table 3. (See http://www.bt.cdc.gov for additional, updated Category Aagent information as well as information concerningCategory B and C agents of bioterrorism and updates.)Category B and C agents are important but are not asreadily disseminated and cause less morbidity andmortality than Category A agents.
Health care facilities confront a different set of is-sues when dealing with a suspected bioterrorism eventcompared with other communicable diseases. An un-derstanding of the epidemiology, modes of transmis-sion, and clinical course of each disease, as well ascarefully drafted plans that specify an approach andrelevant websites and other resources for disease-spe-cific guidance to health care, administrative, and sup-port personnel, are essential for responding to andmanaging a bioterrorism event. Infection control issuesto be addressed include (1) identifying persons whomay be exposed or infected; (2) preventing transmis-sion among patients, HCWs, and visitors; (3) providingtreatment, chemoprophylaxis, or vaccine to potentiallylarge numbers of people; (4) protecting the environ-ment, including the logistical aspects of securing suffi-cient numbers of AIIRs or designating areas for patientcohorts when an insufficient number of AIIRs is avail-able; (5) providing adequate quantities of appropriatePPE; and (6) identifying appropriate staff to care forpotentially infectious patients (eg, vaccinated HCWs forcare of patients with smallpox). The response is likelyto differ for exposures resulting from an intentionalrelease compared with a naturally occurring diseasebecause of the large number of persons that can beexposed at the same time and possible differences inpathogenicity.
Various sources offer guidance for the managementof persons exposed to the most likely agents of bio-terrorism. Federal agency websites (eg, http://www.usamriid.army.mil/publications/index.html and http://www.bt.cdc.gov) and state and county health depart-ment websites should be consulted for the most up-to-date information. Sources of information on specificagents include anthrax,203 smallpox,204-206 plague,207,208
botulinum toxin,209 tularemia,210 and hemorrhagicfever viruses.211,212
I.C.2.a. Pre-Event Administration of Smallpox(Vaccinia) Vaccine to Health Care Workers. Vaccina-tion of HCWsl in preparation for a possible smallpoxexposure has important infection control implica-tions.213-215 These include the need for meticulousscreening for vaccine contraindications in persons atincreased risk for adverse vaccinia events; contain-ment and monitoring of the vaccination site to preventtransmission in the health care setting and at home;and management of patients with vaccinia-related
adverse events.216,217 The pre-event US smallpoxvaccination program of 2003 is an example of theeffectiveness of carefully developed recommendationsfor both screening potential vaccinees for contraindi-cations and vaccination site care and monitoring.Between December 2002 and February 2005, approx-imately 760,000 individuals were vaccinated in theDepartment of Defense and 40,000 in the civilian orpublic health populations, including approximately70,000 who worked in health care settings. No casesof eczema vaccinatum, progressive vaccinia, fetal vac-cinia, or contact transfer of vaccinia were reported inhealth care settings or in military workplaces.218,219
Outside the health care setting, there were 53 cases ofcontact transfer from military vaccinees to close per-sonal contacts (eg, bed partners or contacts during par-ticipation in sports such as wrestling220). All contacttransfers were from individuals who were not followingrecommendations to cover their vaccination sites.Vaccinia virus was confirmed by culture or PCR in 30cases, 2 of which resulted from tertiary transfer. Allrecipients, including 1 breast-fed infant, recoveredwithout complications. Subsequent studies using viralculture and PCR techniques have confirmed the effec-tiveness of semipermeable dressings to containvaccinia.221-224 This experience emphasizes the impor-tance of ensuring that newly vaccinated HCWs adhereto recommended vaccination site care, especially thosecaring for high-risk patients. Recommendations forpre-event smallpox vaccination of HCWs and vaccinia-related infection control recommendations arepublished in the Morbidity and Mortality WeeklyReport,216,225 with updates posted on the CDC’s bioter-rorism website.205
I.C.3. Prions. Creutzfeldt-Jakob disease (CJD) is a rap-idly progressive, degenerative neurologic disorder ofhumans, with an incidence in the United States of ap-proximately 1 person/million population/year.226,227
CJD is believed to be caused by a transmissible protein-aceous infectious agent known as a prion. Infectiousprions are isoforms of a host-encoded glycoproteinknown as the prion protein. The incubation period (ie,time between exposure and and onset of symptoms)varies from 2 years to many decades. However, deathtypically occurs within 1 year of the onset of symptoms.Approximately 85% of CJD cases occur sporadicallywith no known environmental source of infection,and 10% of cases are familial. Iatrogenic transmissionhas occurred, with most cases resulting from treatmentwith human cadaver pituitary-derived growth hormoneor gonadotropin,228,229 from implantation of contami-nated human dura mater grafts,230 or from cornealtransplants.231 Transmission has been linked to theuse of contaminated neurosurgical instruments orstereotactic electroencephalogram electrodes.232-235
Prion diseases in animals include scrapie in sheepand goats, bovine spongiform encephalopathy (BSE,or ‘‘mad cow disease’’) in cattle, and chronic wastingdisease in deer and elk.236 BSE, first recognized in theUnited Kingdom in 1986, was associated with a majorepidemic among cattle that had consumed contami-nated meat and bone meal. The possible transmissionof BSE to humans causing variant CJD (vCJD) was firstdescribed in 1996 and was subsequently found to beassociated with consumption of BSE-contaminated cat-tle products primarily in the United Kingdom. There isstrong epidemiologic and laboratory evidence for acausal association between the causative agent of BSEand vCJD.237 Although most cases of vCJD have beenreported from the United Kingdom, a few cases alsohave been reported from Europe, Japan, Canada, andthe United States. Most persons affected with vCJDworldwide lived in or visited the United Kingdom dur-ing the years of a large outbreak of BSE (1980–1996)and may have consumed contaminated cattle productsduring that time (see http://www.cdc.gov/ncidod/diseases/cjd/cjd.htm). Although there has been no in-digenously acquired vCJD in the United States, thesporadic occurrence of BSE in cattle in North Americahas heightened awareness of the possibility that suchinfections could occur and have led to increased sur-veillance activities. Updated information may be foundat http://www.cdc.gov/ncidod/diseases/cjd/cjd.htm. Thepublic health impact of prion diseases has beenreviewed previously.238
vCJD in humans has different clinical and pathologiccharacteristics than sporadic or classic CJD,239 includ-ing (1) younger median age at death (28 [range, 16 to48] vs 68 years), (2) longer median duration of illness(14 months vs 4 to 6 months), (3) increased frequencyof sensory symptoms and early psychiatric symptomswith delayed onset of frank neurologic signs; and (4) de-tection of prions in tonsillar and other lymphoid tissues,not present in sporadic CJD.240 Similar to sporadic CJD,there have been no reported cases of direct human-to-human transmission of vCJD by casual or environmen-tal contact, droplet, or airborne routes. Ongoing bloodsafety surveillance in the United States has not detectedsporadic CJD transmission through blood transfu-sion;241-243 however, bloodborne transmission of vCJDis believed to have occurred in 2 patients in the UitedKingdom.244,245 The following FDAwebsites provide in-formation on steps currently being taken in the UnitedStates to protect the blood supply from CJD and vCJD:http://www.fda.gov/cber/gdlns/cjdvcjd.htm and http://www.fda.gov/cber/gdlns/cjdvcjdq&a.htm.
Standard Precautions are used when caring for pa-tients with suspected or confirmed CJD or vCJD. How-ever, special precautions are recommended for tissuehandling in the histology laboratory and for conducting
an autopsy, embalming, and coming into contact with abody that has undergone autopsy.246 Recommenda-tions for reprocessing surgical instruments to preventtransmission of CJD in health care settings have beenpublished by the World Health Organization (WHO)and are currently under review at the CDC.
Questions may arise concerning notification of pa-tients potentially exposed to CJD or vCJD through con-taminated instruments and blood products frompatients with CJD or vCJD or at risk of having vCJD.The risk of transmission associated with such expo-sures is believed to be extremely low but may varybased on the specific circumstance. Therefore, consul-tation on appropriate options is advised. The UnitedKingdom has developed several documents that clini-cians and patients in the United States may find use-ful (see http://www.hpa.org.uk/infections/topics_az/cjd/information_documents.htm).
I.C.4. Severe Acute Respiratory Syndrome. SARS is anewly discovered respiratory disease that emerged inChina late in 2002 and spread to several coun-tries.135,140 In particular, mainland China, Hong Kong,Hanoi, Singapore, and Toronto have been significantlyaffected. SARS is caused by SARS-CoV, a previously un-recognized member of the coronavirus family.247,248
The incubation period from exposure to the onset ofsymptoms is typically 2 to 7 days, but can be as longas 10 days and in rare cases even longer.249 The illnessis initially difficult to distinguish from other commonrespiratory infections. Signs and symptoms usually in-clude fever above 38.08C and chills and rigors, some-times accompanied by headache, myalgia, and mild tosevere respiratory symptoms. A radiographic profile ofatypical pneumonia is an important clinical indicatorof possible SARS. Compared with adults, children are af-fected less frequently, have milder disease, and are lesslikely to transmit SARS-CoV.135,249-251 The overall casefatality rate is approximately 6%; underlying diseaseand advanced age increase the risk of mortality (seehttp://www.who.int/csr/sarsarchive/2003_05_07a/en/).
Outbreaks in health care settings, with transmissionto large numbers of HCWs and patients, haa been astriking feature of SARS; undiagnosed infectious pa-tients and visitors have been important initiators ofthese outbreaks.21,252-254 The relative contribution ofpotential modes of transmission is not known pre-cisely. There is ample evidence for droplet and contacttransmission;96,101,113 however, opportunistic airbornetransmission cannot be excluded.101,135-139,149, 254 Forexample, exposure to aerosol-generating procedures(eg, endotracheal intubation, suctioning) has beenassociated with transmission of infection to large num-bers of HCWs outside of the United States.93,94,96,98,253
Therefore, aerosolization of small infectious particlesgenerated during these and other similar procedures
could be a risk factor for transmission to others withina multibed room or shared airspace. A review of the in-fection control literature generated from the SARS out-breaks of 2003 concluded that the greatest risk oftransmission is to those who have close contact, arenot properly trained in use of protective infection con-trol procedures, and do not consistently use PPE, andthat N95 or higher-level respirators may offer addi-tional protection to those exposed to aerosol-generat-ing procedures and high-risk activities.255,256
Organizational and individual factors that affect adher-ence to infection control practices for SARS also wereidentified.256
Control of SARS requires a coordinated, dynamic re-sponse by multiple disciplines in a health care setting.9
Early detection of cases is accomplished by screeningpersons with symptoms of a respiratory infection forhistory of travel to areas experiencing communitytransmission or contact with SARS patients, followedby implementation of respiratory hygiene/cough eti-quette (ie, placing a mask over the patient’s nose andmouth) and physical separation from other patientsin common waiting areas. The precise combinationof precautions to protect HCWs has not yet been deter-mined. At the time of this publication, the CDC recom-mends Standard Precautions, with emphasis on the useof hand hygiene; Contact Precautions, with emphasison environmental cleaning due to the detection ofSARS-CoV RNA by PCR on surfaces in rooms occupiedby SARS patients;138,254,257 and Airborne Precautions,including use of fit-tested NIOSH-approved N95 orhigher-level respirators and eye protection.258 InHong Kong, the use of Droplet and Contact Precautions,including the use of a mask but not a respirator, was ef-fective in protecting HCWs.113 However, in Toronto,consistent use of an N95 respirator was found to beslightly more protective than a mask.93 It is noteworthythat no transmission of SARS-CoV to public hospitalworkers occurred in Vietnam despite inconsistent useof infection control measures, including use of PPE,which suggests other factors (eg, severity of disease,frequency of high-risk procedures or events, environ-mental features) may influence opportunities fortransmission.259
SARS-CoV also has been transmitted in the labora-tory setting through breaches in recommended labo-ratory practices. Research laboratories in whichSARS-CoV was under investigation were the sourceof most cases reported after the first series of out-breaks in the winter and spring of 2003.260,261 Studiesof the SARS outbreaks of 2003 and transmissions oc-curring in the laboratory reaffirm the effectivenessof recommended infection control precautions andhighlight the importance of consistent adherence tothese measures.
Lessons learned from the SARS outbreaks are usefulin devising plans to respond to future public health cri-ses, such as pandemic influenza and bioterrorismevents. Surveillance for cases among patients andHCWs, ensuring availability of adequate supplies andstaffing, and limiting access to health care facilitieswere important factors in the response to SARS.9 Guid-ance for infection control precautions in various set-tings is available at http://www.cdc.gov/ncidod/sars.
I.C.5. Monkeypox. Monkeypox is a rare viral diseasefound mostly in the rain forest countries of Centraland West Africa. The disease is caused by an orthopox-virus that is similar in appearance to smallpox butcauses a milder disease. The only recognized outbreakof human monkeypox in the United States was de-tected in June 2003, after several people became ill af-ter contact with sick pet prairie dogs. Infection in theprairie dogs was subsequently traced to their contactwith a shipment of animals from Africa, including giantGambian rats.262 This outbreak demonstrates the im-portance of recognition and prompt reporting of un-usual disease presentations by clinicians to enableprompt identification of the etiology, as well as the po-tential of epizootic diseases to spread from animal res-ervoirs to humans through personal and occupationalexposure.263
Only limited data on transmission of monkeypoxare available. Transmission from infected animals andhumans is believed to occur primarily through directcontact with lesions and respiratory secretions; air-borne transmission from animals to humans is un-likely but cannot be excluded, and may haveoccurred in veterinary practices (eg, during administra-tion of nebulized medications to ill prairie dogs264). Inhumans, 4 instances of monkeypox transmission inhospitals have been reported in Africa among children,usually related to sharing the same ward or bed.265,266
Additional recent literature documents transmission ofCongo Basin monkeypox in a hospital compound foran extended number of generations.267
There has been no evidence of airborne or any otherperson-to-person transmission of monkeypox in theUnited States, and no new cases of monkeypox havebeen identified since the outbreak in June 2003.268
The outbreak strain is a clade of monkeypox distinctfrom the Congo Basin clade and may have different ep-idemiologic properties (including human-to-humantransmission potential) from monkeypox strains ofthe Congo Basin;269 this awaits further study. Smallpoxvaccine is 85% protective against Congo Basin mon-keypox.270 Because there is an associated case fatalityrate of , 10%, administration of smallpox vaccinewithin 4 days to individuals who have had direct expo-sure to patients or animals with monkeypox is a rea-sonable policy.271 For the most current information
on monkeypox, see http://www.cdc.gov/ncidod/monkeypox/clinicians.htm.
I.C.6. Noroviruses. Noroviruses, formerly referred toas Norwalk-like viruses, are members of the Caliciviri-dae family. These agents are transmitted via contami-nated food or water and from person to person,causing explosive outbreaks of gastrointestinal dis-ease.272 Environmental contamination also has beendocumented as a contributing factor in ongoing trans-mission during outbreaks.273,274 Although norovirusescannot be propagated in cell culture, DNA detection bymolecular diagnostic techniques has brought a greaterappreciation of their role in outbreaks of gastrointesti-nal disease.275 Reported outbreaks in hospitals,132,142,276
nursing homes,274,277-282 cruise ships,283,284,hotels,143,147 schools,148 and large crowded shelters es-tablished for hurricane evacuees285 has demonstratedtheir highly contagious nature, their potentially disrup-tive impact in health care facilities and the community,and the difficulty of controlling outbreaks in settings inwhich people share common facilites and space. Ofnote, there is nearly a 5-fold increase in the risk topatients in outbreaks when a patient is the index casecompared with exposure of patients during outbreakswhen a staff member is the index case.286
The average incubation period for gastroenteritiscaused by noroviruses is 12 to 48 hours, and the clini-cal course lasts 12 to 60 hours.272 Illness is character-ized by acute onset of nausea, vomiting, abdominalcramps, and/or diarrhea. The disease is largely self-lim-ited; rarely, death due to severe dehydration can occur,particularly in elderly persons with debilitating healthconditions.
The epidemiology of norovirus outbreaks shows thateven though primary cases may result from exposure toa fecally contaminated food or water, secondary and ter-tiary cases often result from person-to-person transmis-sion facilitated by contamination of fomites272,287 anddissemination of infectious particles, especially duringthe process of vomiting.132,142,143,147,148,272, 278,279
Widespread, persistent, and inapparent contaminationof the environment and fomites can make outbreaks ex-tremely difficult to control.147,274,283 These clinical ob-servations and the detection of norovirus DNA onhorizontal surfaces 5 feet above the level that might betouched normally suggest that under certain circum-stances, aerosolized particles may travel distances be-yond 3 feet.147 It is hypothesized that infectiousparticles may be aerosolized from vomitus, inhaled,and swallowed. In addition, individuals who are respon-sible for cleaning the environment may be at increasedrisk of infection. Development of disease and transmis-sion may be facilitated by the low infectious dose (ie,, 100 viral particles)288 and the resistance of theseviruses to the usual cleaning and disinfection agents
(ie, they may survive , 10 ppm chlorine).289-291 An al-ternate phenolic agent that was shown to be effectiveagainst feline calicivirus was used for environmentalcleaning in one outbreak.275,292 There are insufficientdata to determine the efficacy of alcohol-based handrubs against noroviruses when the hands are not visiblysoiled.293 Absence of disease in certain individuals dur-ing an outbreak may be explained by protection frominfection conferred by the B histo-blood group anti-gen.294 Consultation on outbreaks of gastroenteritis isavailable through the CDC’s Division of Viral and Rick-ettsial Diseases.295
I.C.7. Hemorrhagic Fever Viruses. HFV is a mixedgroup of viruses that cause serious disease with highfever, skin rash, bleeding diathesis, and, in some cases,high mortality; the resulting disease is referred to asviral hemorrhagic fever (VHF). Among the more com-monly known HFVs are Ebola and Marburg viruses(Filoviridae), Lassa virus (Arenaviridae), Crimean-Congo hemorrhagic fever and Rift Valley Fever virus(Bunyaviridae), and Dengue and Yellow fever viruses(Flaviviridae).212,296 These viruses are transmitted tohumans through contact with infected animals or viaarthropod vectors. Although none of these viruses isendemic in the United States, outbreaks in affectedcountries provide potential opportunities for importa-tion by infected humans and animals. Furthermore,there is a concern that some of these agents could beused as bioweapons.212 Person-to-person transmissionhas been documented for Ebola, Marburg, Lassa, andCrimean-Congo HFVs. In resource-limited health caresettings, transmission of these agents to HCWs, pa-tients, and visitors has been described and in some out-breaks has accounted for a large proportion ofcases.297-299 Transmission within households also hasbeen documented in individuals who had direct con-tact with ill persons or their body fluids, but not inthose who did not have such contact.300
Evidence concerning the transmission of HFVs hasbeen summarized previously.212,301 Person-to-persontransmission is associated primarily with direct bloodand body fluid contact. Percutaneous exposure to con-taminated blood carries a particularly high risk fortransmission and increased mortality.302,303 The find-ing of large numbers of Ebola viral particles in the skinand the lumina of sweat glands has raised concernsthat transmission could occur from direct contact withintact skin, although epidemiologic evidence to sup-port this is lacking.304 Postmortem handling of infectedbodies is an important risk for transmission.300,305,306
In rare situations, cases in which the mode of trans-mission was unexplained among individuals with noknown direct contact have led to speculation thatairborne transmission could have occurred.297 How-ever, airborne transmission of naturally occurring
HFVs in humans has not been documented. A studyof airplane passengers exposed to an in-flight indexcase of Lassa fever found no transmission to anypassengers.307
In the laboratory setting, animals have been infectedexperimentally with Marburg or Ebola virus through di-rect inoculation of the nose, mouth, and/or conjunc-tiva308,309 and by using mechanically generated virus-containing aerosols.310, 311 Transmission of Ebola virusamong laboratory primates in an animal facility hasbeen described.312 The secondarily infected animalswere in individual cages separated by approximately3 meters. Although the possibility of airborne transmis-sion was suggested, the investigators were not able toexclude droplet or indirect contact transmission inthis incidental observation.
Guidance on infection control precautions for HVFstransmitted person-to-person have been published bythe CDC1,211 and by the Johns Hopkins Center for Civil-ian Biodefense Strategies.212 The most recent recom-mendations at the time of publication of thisdocument were posted on the CDC website on May19, 2005.313 Inconsistencies among the various recom-mendations have raised questions about the appropri-ate precautions to use in US hospitals. In less developedcountries, outbreaks of HFVs have been controlled withbasic hygiene, barrier precautions, safe injection prac-tices, and safe burial practices.298,305 The preponder-ance of evidence on HFV transmission indicates thatStandard, Contact, and Droplet Precautions with eyeprotection are effective in protecting HCWs and visitorscoming in contact with an infected patient. Singlegloves are adequate for routine patient care; double-gloving is advised during invasive procedures (eg, sur-gery) that pose an increased risk of blood exposure.Routine eye protection (ie goggles or face shield) is par-ticularly important. Fluid-resistant gowns should beworn for all patient contact. Airborne Precautions arenot required for routine patient care; however, use ofAIIRs is prudent when procedures that could generateinfectious aerosols are performed (eg, endotracheal in-tubation, bronchoscopy, suctioning, autopsy proce-dures involving oscillating saws). N95 or higher-levelrespirators may provide added protection for individ-uals in a room during aerosol-generating procedures(Table 3, Appendix A). When a patient with a syndromeconsistent with hemorrhagic fever also has a history oftravel to an endemic area, precautions are initiated onpresentation and then modified as more information isobtained (Table 2). Patients with hemorrhagic feversyndrome in the setting of a suspected bioweaponsattack should be managed using Airborne Precau-tions, including AIIRs, because the epidemiology ofa potentially weaponized hemorrhagic fever virus isunpredictable.
Siegel et al December 2007 S87
I.D. Transmission Risks Associated WithSpecific Types of Health Care Settings
Numerous factors influence differences in transmis-sion risks among the various health care settings.These factors include the population characteristics(eg, increased susceptibility to infections, type andprevalence of indwelling devices), intensity of care, ex-posure to environmental sources, length of stay, andfrequency of interaction between patients/residentswith each other and with HCWs. These factors, aswell as organizational priorities, goals, and resources,influence how different health care settings adapttransmission prevention guidelines to meet their spe-cific needs.314,315 Infection control management deci-sions are informed by data regarding institutionalexperience/Epidemiology; trends in community andinstitutional HAIs; local, regional, and national Epide-miology; and emerging infectious disease threats.
I.D.1. Hospitals. Infection transmission risks arepresent in all hospital settings. However, certain hospi-tal settings and patient populations have unique condi-tions that predispose patients to infection and meritspecial mention. These are often sentinel sites for theemergence of new transmission risks that may beunique to that setting or present opportunities fortransmission to other settings in the hospital.
I.D.1.a. Intensive Care Units. Intensive care units(ICUs) serve patients who are immunocompromisedby disease state and/or by treatment modalities, aswell as patients with major trauma, respiratory failure,and other life-threatening conditions (eg, myocardialinfarction, congestive heart failure, overdose, stroke,gastrointestinal bleeding, renal failure, hepatic failure,multiorgan system failure, and extremes of age). Al-though ICUs account for a relatively small proportionof hospitalized patients, infections acquired in theseunits account for . 20% of all HAIs.316 In the NationalNosocomial Infection Surveillance (NNIS) system,26.6% of HAIs were reported from ICU and high-risknursery (neonatal ICU [NICU]) patients in 2002 (NNIS,unpublished data). This patient population has in-creased susceptibility to colonization and infection, es-pecially with MDROs and Candida spp,317,318 becauseof underlying diseases and conditions, the invasivemedical devices and technology used in their care(eg central venous catheters and other intravasculardevices, mechanical ventilators, extracorporeal mem-brane oxygenation, hemodialysis/filtration, pacemakers,implantable left-ventricular assist devices), the fre-quency of contact with HCWs, prolonged lengths of stay,and prolonged exposure to antimicrobial agents.319-330
Furthermore, adverse patient outcomes in this settingare more severe and are associated with a higher mortal-ity.331 Outbreaks associated with various bacterial,
fungal, and viral pathogens due to common-sourceand person-to-person transmissions are frequent inadult ICUs and pediatric ICUs (PICUs).31,332-337
I.D.1.b. Burn Units. Burn wounds can provide opti-mal conditions for colonization, infection, and trans-mission of pathogens; infection acquired by burnpatients is a frequent cause of morbidity and mortal-ity.319,338,339 The risk of invasive burn wound infectionis particularly high in patients with a burn injury in-volving . 30% of the total body surface area(TBSA).340,341 Infections occurring in patients withburn injuries involving , 30% of the TBSA are usuallyassociated with the use of invasive devices. MSSA,MRSA, enterococci (including VRE), gram-negative bac-teria, and Candida spp are prevalent pathogens in burninfections,53,339,342-349 and outbreaks of these orga-nisms have been reported.350-353 Shifts over time inthe predominance of pathogens causing infections inburn patients often lead to changes in burn care prac-tices.342,354-357 Burn wound infections caused byAspergillus spp or other environmental molds mayresult from exposure to supplies contaminated duringconstruction358 or to dust generated during construc-tion or other environmental disruption.359
Hydrotherapy equipment is an important environ-mental reservoir of gram-negative organisms. Its usein burn care is discouraged based on demonstrated as-sociations between the use of contaminated hydrother-apy equipment and infections. Burn wound infectionsand colonization, as well as bloodstream infections,caused by multidrug-resistant P aeruginosa,360 Acineto-bacter baumannii,361 and MRSA351 have been associ-ated with hydrotherapy; thus, excision of burnwounds in operating rooms is the preferred approach.
Advances in burn care (specifically, early excisionand grafting of the burn wound, use of topical antimi-crobial agents, and institution of early enteral feeding)have led to decreased infectious complications. Otheradvances have included prophylactic antimicrobialuse, selective digestive decontamination, and use of an-timicrobial-coated catheters; however, few epidemio-logic studies and no efficacy studies have beenperformed to investigate the relative benefit of thesemeasures.356
There is no consensus on the most effective infec-tion control practices to prevent transmission of infec-tions to and from patients with serious burns (eg,single-bed rooms,357 laminar flow,362 and high-effi-ciency particulate air [HEPA] filtration,359 or maintain-ing burn patients in a separate unit with no exposureto patients or equipment from other units363). Therealso is controversy regarding the need for and typeof barrier precautions in the routine care of burn pa-tients. One retrospective study demonstrated the effi-cacy and cost-effectiveness of a simplified barrier
S88 Vol. 35 No. 10 Supplement 2 Siegel et al
isolation protocol for wound colonization, emphasiz-ing handwashing and use of gloves, caps, masks, andimpermeable plastic aprons (rather than isolationgowns) for direct patient contact.364 However, todate no studies have determined the most effectivecombination of infection control precautions for usein burn settings. Prospective studies in this area areneeded.
I.D.1.c. Pediatrics. Studies of the epidemiology ofHAIs in children have identified unique infection con-trol issues in this population.63,64,365-369 Pediatric ICUpatients and the lowest birth weight babies in theNICU monitored in the NNIS system have had highrates of central venous catheter–associated blood-stream infections.64,319,368-371 In addition, there is ahigh prevalence of community-acquired infectionsamong hospitalized infants and young children whohave not yet become immune either by vaccinationor by natural infection. This results in more patientsand their sibling visitors with transmissible infectionsin pediatric health care settings, especially during sea-sonal epidemics (eg, pertussis;36,40,41 respiratory viralinfections. including those caused by RSV,24 influenzaviruses,372 parainfluenza virus,373 human metapneu-movirus,374 and adenoviruses;375 rubeola [measles];34
varicella [chickenpox];376 and rotavirus38,377).Close physical contact between HCWs and infants
and young children (eg. cuddling, feeding, playing,changing soiled diapers, and cleaning copious uncon-trolled respiratory secretions) provides abundant op-portunities for transmission of infectious material.Such practices and behaviors as congregation of chil-dren in play areas where toys and bodily secretionsare easily shared and rooming-in of family memberswith pediatric patients can further increase the riskof transmission. Pathogenic bacteria have been recov-ered from toys used by hospitalized patients;378 con-taminated bath toys were implicated in an outbreakof multidrug-resistant P. aeruginosa on a pediatric on-cology unit.80 In addition, several patient factors in-crease the likelihood that infection will result fromexposure to pathogens in health care settings (eg, im-maturity of the neonatal immune system, lack of previ-ous natural infection and resulting immunity,prevalence of patients with congenital or acquired im-mune deficiencies, congenital anatomic anomalies,and use of life-saving invasive devices in NICUs andPICUs).63 There are theoretical concerns that infectionrisk will increase in association with innovative prac-tices used in the NICU for the purpose of improvingdevelopmental outcomes, Such factors include co-bedding379 and kangaroo care,380 which may increaseopportunity for skin-to-skin exposure of multiple ges-tation infants to each other and to their mothers, re-spectively; although the risk of infection actually may
be reduced among infants receiving kangaroo care.381
Children who attend child care centers382,383 and pedi-atric rehabilitation units384 may increase the overallburden of antimicrobial resistance by contributing tothe reservoir of CA-MRSA.385-390 Patients in chroniccare facilities may have increased rates of colonizationwith resistant garm-negative bacilli and may be sour-ces of introduction of resistant organisms to acutecare settings.50
I.D.2. Nonacute Health Care Settings. Health care isprovided in various settings outside of hospitals, in-cluding long-term care facilities (LTCFs) (eg nursinghomes), homes for the developmentally disabled, be-havioral health service settings, rehabilitation centers,and hospices.391 In addition, health care may be pro-vided in non–health care settings, such as workplaceswith occupational health clinics, adult day care centers,assisted-living facilities, homeless shelters, jails andprisons, school clinics, and infirmaries. Each of thesesettings has unique circumstances and population risksthat must be considered when designing and imple-menting an infection control program. Several of themost common settings and their particular challengesare discussed below. Although this guideline does notaddress each setting, the principles and strategies pro-vided herein may be adapted and applied asappropriate.
I.D.2.a. Long-Term Care. The designation LTCF ap-plies to a diverse group of residential settings, rangingfrom institutions for the developmentally disabled tonursing homes for the elderly and pediatric chroniccare facilities.392-394 Nursing homes for the elderly pre-dominate numerically and frequently represent long-term care as a group of facilities. Approximately 1.8million Americans reside in the nation’s 16,500 nurs-ing homes.395 Estimates of HAI rates of 1.8 to 13.5per 1000 resident-care days have been reported, witha range of 3 to 7 per 1000 resident-care days in themore rigorous studies.396-400 The infrastructure de-scribed in the Department of Veterans Affairs’ nursinghome care units is a promising example for the devel-opment of a nationwide HAI surveillance system forLTCFs.401
LCTFs are different from other health care settingsin that elderly patients at increased risk for infectionare brought together in one setting and remain in thefacility for extended periods; for most residents, it istheir home. An atmosphere of community is fostered,and residents share common eating and living areasand participate in various facility-sponsored activi-ties.402,403 Because able residents interact freely witheach other, controlling infection transmission in thissetting can be challenging.404 A residents who is colo-nized or infected with certain microorganisms are insome cases restricted to his or her room. However,
Siegel et al December 2007 S89
because of the psychosocial risks associated with suchrestriction, balancing psychosocial needs with infec-tion control needs is important in the LTCF set-ting.405-408 Documented LTCF outbreaks have beencaused by various viruses (eg, influenza virus,35,409-411
rhinovirus,412 adenovirus [conjunctivitis],413 norovi-rus274,277,278,280) and bacteria, including group A strep-tococcus,162, B pertussis,414 nonsusceptible Spneumoniae,197,198 other MDROs, and C difficile415).These pathogens can lead to substantial morbidityand mortality, as well as increased medical costs;prompt detection and implementation of effective con-trol measures are needed.
Risk factors for infection are prevalent among LTCFresidents.394,416,417 Age-related declines in immunitymay affect the response to immunizations for influenzaand other infectious agents and increase the suscepti-bility to tuberculosis. Immobility, incontinence, dys-phagia, underlying chronic diseases, poor functionalstatus, and age-related skin changes increase suscepti-bility to urinary, respiratory, and cutaneous and soft tis-sue infections, whereas malnutrition can impairwound healing.418-422 Medications (eg, drugs that affectlevel of consciousness, immune function, gastric acidsecretions, and normal flora, including antimicrobialtherapy) and invasive devices (eg, urinary cathetersand feeding tubes) heighten the susceptibility to infec-tion and colonization in LTCF residents.423-425 Finally,limited functional status and total dependence onHCWs for activities of daily living have been identifiedas independent risk factors for infection400,416,426 andfor colonization with MRSA427,428 and ESBL-producingKlebsiella pneumoniae.429 Several position papers andreview articles provide guidance on various aspects ofinfection control and antimicrobial resistance inLTCFs.405-407,430-435 The Centers for Medicare and Med-icaid Services has established regulations for the pre-vention of infection in LTCFs.436
Because residents of LTCFs are hospitalized fre-quently, they can transfer pathogens between LTCFsand health care facilities in which they receivecare.8,437-440 This also is true for pediatric long-termcare populations. Pediatric chronic care facilities havebeen associated with the importation of extended-spectrum cephalosporin-resistant, gram-negativebacilli into a PICU.50 Children from pediatric rehabilita-tion units may contribute to the reservoir of commu-nity-associated MRSA.384,388-390
I.D.2.b. Ambulatory Care. Over the past decade,health care delivery in the United States has shiftedfrom the acute, inpatient hospital to various ambula-tory and community-based settings, including thehome. Ambulatory care is provided in hospital-basedoutpatient clinics, nonhospital-based clinics and physi-cians’ offices, public health clinics, free-standing
dialysis centers, ambulatory surgical centers, urgentcare centers, and other setting. In 2000, there were83 million visits to hospital outpatient clinics andmore than 823 million visits to physicians’ offices;441
ambulatory care now accounts for most patient en-counters with the health care system.442 Adaptingtransmission prevention guidelines to these settings ischallenging, because patients remain in common areasfor prolonged periods waiting to be seen by a healthcare provider or awaiting admission to the hospital, ex-amination or treatment rooms are turned aroundquickly with limited cleaning, and infectious patientsmay not be recognized immediately. Furthermore, im-munocompromised patients often receive chemother-apy in infusion rooms, where they stay for extendedperiods along with other types of patients.
Little data exist on the risk of HAIs in ambulatorycare settings, with the exception of hemodialysis cen-ters.18,443,444 Transmission of infections in outpatientsettings has been reviewed in 3 studies.445-447 Good-man and Solomon445 summarized 53 clusters of infec-tions associated with the outpatient setting between1961 and 1990. Overall, 29 clusters were associatedwith common source transmission from contaminatedsolutions or equipment, 14 were associated with per-son-to-person transmission from or involving HCWs,and 10 were associated with airborne or droplet trans-mission among patients and health care workers.Transmission of bloodborne pathogens (ie, HBV, HCV,and, rarely, HIV) in outbreaks, sometimes involvinghundreds of patients, continues to occur in ambulatorysettings. These outbreaks often are related to commonsource exposures, usually a contaminated medical de-vice, multidose vial, or intravenous solution.82,448-452 Inall cases, transmission has been attributed to failure toadhere to fundamental infection control principles, in-cluding safe injection practices and aseptic technique.This subject has been reviewed, and recommended in-fection control and safe injection practices have beensummarized.453
Airborne transmission of M tuberculosis and mea-sles in ambulatory settings, most often emergency de-partments, has been reported.34,127,445,447,454-456
Measles virus was transmitted in physicians’ officesand other outpatient settings during an era when im-munization rates were low and measles outbreaks inthe community were occurring regularly.34,122,457 Ru-bella has been transmitted in the outpatient obstetricsetting;33 there are no published reports of varicellatransmission in the outpatient setting. In the ophthal-mology setting, adenovirus type 8 epidemic keratocon-junctivitis has been transmitted through incompletelydisinfected ophthalmology equipment and/or fromHCWs to patients, presumably by contaminatedhands.17,445,447,458-461
S90 Vol. 35 No. 10 Supplement 2 Siegel et al
Preventing transmission in outpatient settings ne-cessitates screening for potentially infectious sympto-matic and asymptomatic individuals, especially thoseat possible risk for transmitting airborne infectiousagents (eg, M tuberculosis, varicella-zoster virus, rube-ola [measles]), at the start of the initial patient encoun-ter. On identification of a potentially infectious patient,implementation of prevention measures, includingprompt separation of potentially infectious patientsand implementation of appropriate control measures(eg, respiratory hygiene/cough etiquette and Transmis-sion-Based Precautions) can decrease transmissionrisks.9,12 Transmission of MRSA and VRE in outpatientsettings has not been reported, but the association ofCA-MRSA in HCWs working in an outpatient HIV clinicwith environmental CA-MRSA contamination in thatclinic suggests the possibility of transmission in thatsetting.462 Patient-to-patient transmission of Burkhol-deria spp and P aeruginosa in outpatient clinics foradults and children with cystic fibrosis has beenconfirmed.463,464
I.D.2.c. Home Care. Home care in the United Statesis delivered by more than 20,000 provider agencies, in-cluding home health agencies, hospices, durable med-ical equipment providers, home infusion therapyservices, and personal care and support services pro-viders. Home care is provided to patients of all ageswith both acute and chronic conditions. The scope ofservices ranges from assistance with activities of dailyliving and physical and occupational therapy to thecare of wounds, infusion therapy, and chronic ambula-tory peritoneal dialysis.
The incidence of infection in home care patients,other than that associated with infusion therapy, hasnot been well studied.465-470 However, data collectionand calculation of infection rates have been done forcentral venous catheter–associated bloodstream infec-tions in patients receiving home infusion therapy469-
473 and for the risk of blood contact through percutane-ous or mucosal exposures, demonstrating that surveil-lance can be performed in this setting.474 Draftdefinitions for home care–associated infections havebeen developed.475
Transmission risks during home care are presumedto be minimal. The main transmission risks to homecare patients are from an infectious home care pro-vider or contaminated equipment; a provider also canbe exposed to an infectious patient during home visits.Because home care involves patient care by a limitednumber of personnel in settings without multiple pa-tients or shared equipment, the potential reservoir ofpathogens is reduced. Infections of home care pro-viders that could pose a risk to home care patientsinclude infections transmitted by the airborne or drop-let routes (eg, chickenpox, tuberculosis, influenza),
skin infestations (eg, scabies69 and lice), and infectionstransmitted by direct or indirect contact (eg, impetigo).There are no published data on indirect transmissionof MDROs from one home care patient to another,although this is theoretically possible if contaminatedequipment is transported from an infected or colonizedpatient and used on another patient. Of note, investiga-tions of the first case of VISA in home care186 and thefirst 2 reported cases of VRSA178,180,181,183 found noevidence of transmission of VISA or VRSA to otherhome care recipients. Home health care also may con-tribute to antimicrobial resistance; a review of outpa-tient vancomycin use found that 39% of recipientsdid not receive prescribed antibiotics according to rec-ommended guidelines.476
Although most home care agencies implement poli-cies and procedures aimed at preventing transmissionof organisms, the current approach is based on the ad-aptation of the 1996 Guideline for Isolation Precautionsin Hospitals,1 as well as other professional guid-ance.477,478 This issue has proven very challenging tothe home care industry, and practice has been incon-sistent and frequently not evidence-based. For exam-ple, many home health agencies continue to observe‘‘nursing bag technique,’’ a practice that prescribesthe use of barriers between the nursing bag and envi-ronmental surfaces in the home.479 Although thehome environment may not always appear clean, theuse of barriers between 2 noncritical surfaces hasbeen questioned.480,481 Opportunites exist to conductresearch in home care related to infection transmissionrisks.482
I.D.2.d. Other Sites of Health Care Delivery. Facil-ities that are not primarily health care settings butin which health care is delivered include clinics incorrectional facilities and shelters. Both of these set-tings can have suboptimal features, such as crowdedconditions and poor ventilation. Economically disad-vantaged individuals who may have chronic illnessesand health care problems related to alcoholism, in-jected drug use, poor nutrition, and/or inadequateshelter often receive their primary health care atsuch sites.483 Infectious diseases of special concernfor transmission include tuberculosis, scabies, respira-tory infections (eg, N meningitides, S pneumoniae), sex-ually transmitted and bloodborne diseases (eg, HIV,HBV, HCV, syphilis, gonorrhea), hepatitis A virus, diar-rheal agents such as norovirus, and foodbornediseases.285,484-487 A high index of suspicion for tuber-culosis and CA-MRSA in these populations is needed;outbreaks in these settings or among the populationsthey serve have been reported.488-496
Patient encounters in these types of facilities pro-vide an opportunity to deliver recommended immuni-zations and screen for M tuberculosis infection, along
Siegel et al December 2007 S91
with diagnosing and treating acute illnesses.497 Recom-mended infection control measures in these nontradi-tional areas designated for health care delivery arethe same as for other ambulatory care settings. There-fore, these settings must be equipped to observeStandard Precautions and, when indicated, Transmis-sion-Based Precautions.
I.E. Transmission Risks Associated With SpecialPatient Populations
As new treatments emerge for complex diseases,unique infection control challenges associated withspecial patient populations must be addressed.
I.E.1. Immunocompromised Patients. Patients whohave congenital primary immune deficiencies or ac-quired disease (eg. treatment-induced immune defi-ciencies) are at increased risk for numerous types ofinfections while receiving health care; these patientsmay be located throughout the health care facility.The specific immune system defects determine thetypes of infections most likely to be acquired (eg, viralinfections are associated with Tcell defects, and fungaland bacterial infections occur in patients who are neu-tropenic). As a general group, immunocompromisedpatients can be cared for in the same environment asother patients; however, it is always advisable to mini-mize exposure to other patients with transmissible in-fections, such as influenza and other respiratoryviruses.498,499 The use of more intense chemotherapyregimens for treatment of childhood leukemia maybe associated with prolonged periods of neutropeniaand suppression of other components of the immunesystem, extending the period of infection risk and rais-ing the concern that additional precautions may be in-dicated for select groups.500,501 With the application ofnewer and more intense immunosuppressive therapiesfor various medical conditions (eg, rheumatologic dis-ease,502, 503 inflammatory bowel disease504), immuno-suppressed patients are likely to be more widelydistributed throughout a health care facility ratherthan localized to single patient units (eg, hematology-oncology). Guidelines for preventing infections in cer-tain groups of immunocompromised patients havebeen published previously.15,505,506
Published data provide evidence to support placingpatients undergoing allogeneic HSCT in a PE.15,157,158
In addition, guidelines have been developed that ad-dress the special requirements of these immunocom-promised patients, including use of antimicrobialprophylaxis and engineering controls to create a PEfor the prevention of infections caused by Aspergillusspp and other environmental fungi.11,14,15 As more in-tense chemotherapy regimens associated with pro-longed periods of neutropenia or graft-versus-host
disease are implemented, the period of risk and dura-tion of environmental protection may need to be pro-longed beyond the traditional 100 days.507
I.E.2. Cystic Fibrosis Patients. Patients with cysticfibrosis (CF) require special consideration when devel-oping infection control guidelines. Compared withother patients, CF patients require additional protec-tion to prevent transmission from contaminated respi-ratory therapy equipment.508-512 Such infectious agentsas B cepacia complex and P aeruginosa.463,464,513,514
have unique clinical and prognostic significance. InCF patients, B cepacia infection has been associatedwith increased morbidity and mortality,515-517 whereasdelayed acquisition of chronic P aeruginosa infectionmay be associated with an improved long-term clinicaloutcome.518,519
Person-to-person transmission of B cepacia complexhas been demonstrated among children516 andadults520 with CF in health care settings463,521 andfrom various social contacts,522 most notably atten-dance at camps for patients with CF523 and among sib-lings with CF.524 Successful infection control measuresused to prevent transmission of respiratory secretionsinclude segregation of CF patients from each other inambulatory and hospital settings (including use of pri-vate rooms with separate showers), environmental de-contamination of surfaces and equipmentcontaminated with respiratory secretions, eliminationof group chest physiotherapy sessions, and disbandingof CF camps.97,525 The Cystic Fibrosis Foundation haspublished a consensus document with evidence-basedrecommendations for infection control practices in CFpatients.20
I.F. New Therapies Associated With PotentiallyTransmissible Infectious Agents
I.F.1. Gene Therapy. Gene therapy has has been at-tempted using various viral vectors, including nonrep-licating retroviruses, adenoviruses, adeno-associatedviruses, and replication-competent strains of poxvi-ruses. Unexpected adverse events have restricted theprevalence of gene therapy protocols.
The infectious hazards of gene therapy are theoreti-cal at this time but require meticulous surveillance dueto the possible occurrence of in vivo recombinationand the subsequent emergence of a transmissiblegenetically altered pathogen. The greatest concernattends the use of replication-competent viruses,especially vaccinia. To date, no reports have describedtransmission of a vector virus from a gene therapyrecipient to another individual, but surveillance isongoing. Recommendations for monitoring infectioncontrol issues throughout the course of gene therapytrials have been published.526-528
S92 Vol. 35 No. 10 Supplement 2 Siegel et al
I.F.2. Infections Transmitted Through Blood,Organs, and Other Tissues. The potential hazard oftransmitting infectious pathogens through biologicproducts is a small but ever-present risk, despite donorscreening. Reported infections transmitted by transfu-sion or transplantation include West Nile virus infec-tion,529 cytomegalovirus infection,530 CJD,230
hepatitis C,531 infections with Clostridium spp532 andgroup A streptococcus,533 malaria,534 babesiosis,535
and rabies.538,539 Therefore, it is important to considerreceipt of biologic products when evaluating patientsfor potential sources of infection.
I.F.3. Xenotransplantation. Transplantation of non-human cells, tissues, and organs into humans poten-tially exposes patients to zoonotic pathogens.Transmission of known zoonotic infections (eg, trichi-nosis from porcine tissue) is of concern. Also ofconcern is the possibility that transplantation of non-human cells, tissues, or organs may transmit previ-ously unknown zoonotic infections (xenozoonoses) toimmunosuppressed human recipients. Potential infec-tions that potentially could accompany transplantationof porcine organs have been described previously.540
Guidelines from the US Public Health Service addressmany infectious diseases and infection control issuesthat surround the developing field of xenotransplanta-tion;541 work in this area is ongoing.
PART II: FUNDAMENTAL ELEMENTS NEEDED TOPREVENT TRANSMISSION OF INFECTIOUSAGENTS IN HEALTH CARE SETTINGS
II.A. Health Care System Components ThatInfluence the Effectiveness of Precautions toPrevent Transmission
II.A.1. Administrative Measures. Health care organi-zations can demonstrate a commitment to preventingtransmission of infectious agents by incorporating in-fection control into the objectives of the organization’spatient and occupational safety programs.542-546 An in-frastructure designed to guide, support, and monitoradherence to Standard Precautions and Transmission-Based Precautions434,547,548 will facilitate fulfillmentof the organization’s mission and achievement of theJoint Commission on Accreditation of Health CareOrganizations’ patient safety goal to decrease HAIs.549
Policies and procedures that explain how StandardPrecautions and Transmission-Based Precautions areapplied, including systems used to identify and com-municate information on patients with potentiallytransmissible infectious agents, are essential to ensurethe success of these measures. These policies and pro-cedures may vary according to the characteristics ofthe organization.
A key administrative measure is the provision of fis-cal and human resources for maintaining infectioncontrol and occupational health programs that are re-sponsive to emerging needs. Specific components in-clude bedside nurse550 and infection prevention andcontrol professional (ICP) staffing levels,551 inclusionof ICPs in facility construction and design decisions,11
clinical microbiology laboratory support,552,553
adequate supplies and equipment including facilityventilation systems,11 adherence monitoring,554 assess-ment and correction of system failures that contributeto transmission,555,556 and provision of feedback toHCWs and senior administrators.433,547,548,557 Thepositive influence of institutional leadership has beendemonstrated repeatedly in studies of HCWs’ adher-ence to recommended hand hygiene practices.176,177,
433,547,548,558-563 Health care administrators’ involve-ment in the infection control processes can improvetheir awareness of the rationale and resource require-ments for following recommended infection controlpractices.
Several administrative factors may affect the trans-mission of infectious agents in health care settings, in-cluding the institutional culture, individual HCWbehavior, and the work environment. Each of theseareas is suitable for performance improvement moni-toring and incorporation into the organization’s patientsafety goals.542,543,545,564
II.A.1.a. Scope of Work and Staffing Needs forInfection Control Professionals. The effectiveness ofinfection surveillance and control programs in prevent-ing nosocomial infections in USt hospitals was as-sessed by the CDC through the Study on the Efficacyof Nosocomial Infection Control (SENIC Project) con-ducted between 1970 and 1976.565 In a representativesample of US general hospitals, those with a trained in-fection control physician or microbiologist involved inan infection control program and at least 1 infectioncontrol nurse per 250 beds were associated with a32% lower rate of the 4 infections studied (CVC-associ-ated bloodstream infections, ventilator-associatedpneumonias, catheter-related urinary tract infections,and surgical site infections).
Since the publication of that landmark study, respon-sibilities of ICPs have expanded commensurate with thegrowing complexity of the health care system, the pa-tient populations served, and the increasing numbersof medical procedures and devices used in all types ofhealth care settings. The scope of work of ICPs was firstassessed in 1982566-568 by the Certification Board of In-fection Control, and has been reassessed every 5 yearssince that time.557,569-571 The findings of these analyseshave been used to develop and update the InfectionControl Certification Examination, which was first of-fered in 1983. With each new survey, it becomes
Siegel et al December 2007 S93
increasingly apparent that the role of the ICP is growingin complexity and scope beyond traditional infectioncontrol activities in acute care hospitals. Activitiescurrently assigned to ICPs in response to emerging chal-lenges include (1) surveillance and infection preventionat facilities other than acute care hospitals (eg, ambula-tory clinics, day surgery centers, LTCFs, rehabilitationcenters, home care); (2) oversight of employee healthservices related to infection prevention (eg, assessmentof risk and administration of recommended treatmentafter exposure to infectious agents, tuberculosis screen-ing, influenza vaccination, respiratory protection fittesting, and administration of other vaccines as indi-cated, such as smallpox vaccine in 2003); (3) prepared-ness planning for annual influenza outbreaks,pandemic influenza, SARS, and bioweapons attacks;(4) adherence monitoring for selected infection controlpractices; (5) oversight of risk assessment and imple-mentation of prevention measures associated withconstruction and renovation; (6) prevention of trans-mission of MDROs; (7) evaluation of new medical pro-ducts that could be associated with increasedinfection risk (eg, intravenous infusion materials); (8)communication with the public, facility staff, and stateand local health departments concerning infection con-trol–related issues; and (9) participation in local andmulticenter research projects.433,548,551,557,572,573
None of the Certification Board of Infection Controljob analyses addressed specific staffing requirementsfor the identified tasks, although the surveys did in-clude information about hours worked; the 2001 sur-vey included the number of ICPs assigned to theresponding facilities.557 There is agreement in the liter-ature that a ratio of 1 ICP per 250 acute care beds is nolonger adequate to meet current infection controlneeds; a Delphi project that assessed staffing needs ofinfection control programs in the 21st century con-cluded that a ratio of 0.8 to 1.0 ICP per 100 occupiedacute care beds is an appropriate staffing level.551 Asurvey of participants in the NNIS system found an av-erage daily patient census of 115 per ICP.315 Results ofother studies have been similar: 3 per 500 beds forlarge acute care hospitals, 1 per 150 to 250 beds inLTCFs, and 1.56 per 250 in small rural hospitals.572,574
The foregoing demonstrates that infection controlstaffing no longer can be based on patient censusalone, but rather must be determined by the scope ofthe program, characteristics of the patient population,complexity of the health care system, tools availableto assist personnel to perform essential tasks (eg,electronic tracking and laboratory support for sur-veillance), and unique or urgent needs of the institu-tion and community.551 Furthermore, appropriatetraining is required to optimize the quality of workperformed.557,571,575
II.A.1.a.i. Infection Control Nurse Liaison. Desig-nating a bedside nurse on a patient care unit as an infec-tion control liaison or ‘‘link nurse’’ is reported to be aneffective adjunct to enhance infection control at theunit level.576-581 Such individuals receive training in ba-sic infection control and have frequent communicationwith ICPs, but maintain their primary role as bedsidecaregiver on their units. The infection control nurse liai-son increases the awareness of infection control at theunit level. He or she is especially effective in implemen-tating new policies or control interventions because ofthe rapport with individuals on the unit, an understand-ing of unit-specific challenges, and ability to promotestrategies that are most likely to be successful in thatunit. This position is an adjunct to, not a replacementfor, fully trained ICPs. Furthermore, the infection controlliaison nurses should not be counted when consideringICP staffing.
II.A.1.b. Bedside Nurse Staffing. There is increasingevidence that the level of bedside nurse staffing influ-ences the quality of patient care.582,583 Adequate nurs-ing staff makes it more likely that infection controlpractices, including hand hygiene, Standard Precau-tions, and Transmission-Based Precautions, will begiven appropriate attention and applied correctly andconsistently.551 A national multicenter study reportedstrong and consistent inverse relationships betweennurse staffing and 5 adverse outcomes in medical pa-tients, 2 of which were HAIs (urinary tract infectionsand pneumonia).582 The association of nursing staffshortages with increased rates of HAI has been demon-strated in several outbreaks in hospitals and LTCFs, andwith increased transmission of hepatitis C virus in dial-ysis units.22,417,550,584-596 In most cases, when staffingwas improved as part of a comprehensive control inter-vention, the outbreak ended or the HAI rate declined. In2 studies,589,595 the composition of the nursing staff(‘‘pool’’ or ‘‘float’’ vs regular staff nurses) influenced therate of primary bloodstream infections, with an increasedinfection rate occurring when the proportion of regularnurses decreased and that of pool nurses increased.
II.A.1.c. Clinical Microbiology LaboratorySupport. The critical role of the clinical microbiologylaboratory in infection control and health care epidemi-ology has been well described552,553,597-599 and is sup-ported by the Infectious Disease Society of America’spolicy statement on the consolidation of clinical micro-biology laboratories published in 2001.552 The clinicalmicrobiology laboratory contributes to preventing trans-mission of infectious diseases in health care settings bypromptly detecting and reporting epidemiologicallyimportant organisms, identifying emerging patterns ofantimicrobial resistance, and assessing the effectivenessof recommended precautions to limit transmissionduring outbreaks.597 Outbreaks of infections may be
S94 Vol. 35 No. 10 Supplement 2 Siegel et al
recognized first by laboratorians.161 Health care organi-zations need to ensure the availability of the recommen-ded scope and quality of laboratory services, a sufficientnumber of appropriately trained laboratory staff mem-bers, and systems to promptly communicate epidemio-logically important results to those who will take action(eg, providers of clinical care, infection control staff,health care epidemiologists, and infectious disease con-sultants).600 As concerns about emerging pathogensand bioterrorism grow, the role of the clinical microbi-ology laboratory assumes ever-greater importance. Forhealth care organizations that outsource microbiologylaboratory services (eg, ambulatory care, home care,LTCFs, smaller acute care hospitals), it is important tospecify by contract the types of services (eg, periodic in-stitution-specific aggregate susceptibility reports) re-quired to support infection control.
Several key functions of the clinical microbiologylaboratory are relevant to this guideline:
d Antimicrobial susceptibility by testing and interpreta-tion in accordance with current guidelines developedby the National Committee for Clinical LaboratoryStandards, known as the Clinical and Laboratory Stan-dards Institute since 2005,601 for the detection ofemerging resistance patterns602,603 and for the prepa-ration, analysis, and distribution of periodic cumula-tive antimicrobial susceptibility summary reports.604-
606 Although not required, clinical laboratories ideallyshould have access to rapid genotypic identification ofbacteria and their antibiotic resistance genes.607
d Performance of surveillance cultures when appro-priate (including retention of isolates for analysis),to assess patterns of infection transmission andeffectiveness of infection control interventions atthe facility or organization. Microbiologists assist indecision making regarding the indications for initiat-ing and discontinuing active surveillance programsand optimizing the use of laboratory resources.
d Molecular typing, onsite or outsourced, to investigateand control health care–associated outbreaks.608
d Application of rapid diagnostic tests to support clini-cal decisions involving patient treatment, room se-lection, and implementation of control measures,including barrier precautions and use of vaccine orchemoprophylaxis agents (eg, influenza,609-611 B per-tussis,612, RSV,613, 614 and enteroviruses615). The mi-crobiologist provides guidance to limit rapid testingto clinical situations in which rapid results influencepatient management decisions, and also providesoversight of point-of-care testing performed by non-laboratory HCWs.616
d Detection and rapid reporting of epidemiologicallyimportant organisms, including those that are report-able to public health agencies.
d Implementation of a quality control program to en-sure that testing services are appropriate for the pop-ulation being served and are stringently evaluated forsensitivity, specificity, applicability, and feasibility.
d Participation in a multidisciplinary team to developand maintain an effective institutional program forthe judicious use of antimicrobial agents.617,618
II.A.2. Institutional Safety Culture and Organiza-tional Characteristics. Safety culture (or safety climate)refers to a work environment in which a shared com-mitment to safety on the part of management and theworkforce is understood and maintained.558,619,620
The authors of the Institute of Medicine’s report titledTo Err is Human542 acknowledged that causes of med-ical error are multifaceted but emphasized the pivotalrole of system failures and the benefits of a safety cul-ture. A safety culture is created through (1) the actionsthat management takes to improve patient and workersafety, (2) worker participation in safety planning, (3)the availability of appropriate PPE, (4) the influenceof group norms regarding acceptable safety practices,and (5) the organization’s socialization process fornew personnel. Safety and patient outcomes can be en-hanced by improving or creating organizational char-acteristics within patient care units, as demonstratedby studies of surgical ICUs.621,622 Each of these factorshas a direct bearing on adherence to transmission pre-vention recommendations.256 Measurement of an in-stitution’s culture of safety is useful in designingimprovements in health care.623,624 Several hospital-based studies have linked measures of safety culturewith both employee adherence to safe practices andreduced exposures to blood and body fluids.625-631
One study of hand hygiene practices concluded thatimproved adherence requires integration of infectioncontrol into the organization’s safety culture.560 Severalhospitals that are part of the Veterans Administrationhealth care system have taken specific steps toward im-proving the safety culture, including error-reportingmechanisms, root cause analyses of identified prob-lems, safety incentives, and employee education.632-634
II.A.3. Adherence of Health Care Workers to Rec-ommended Guidelines. HCWs’ adherence to recom-mended infection control practices decreases thetransmission of infectious agents in health care set-tings.116,561,635-639 Several observational studies haveshown limited adherence to recommended practices byHCWs.558,639-656 Observed adherence to universal pre-cautions ranged from 43% to 89%.640,641,648,650,651 Thedegree of adherence often depended on the specificpractice that was assessed and, for glove use, thecircumstance in which the practice was applied. Ob-served rates of appropriate glove use has ranged froma low of 15%644 to a high of 82%.649 However, 92%
Siegel et al December 2007 S95
and 98% adherence with glove use have been reportedduring arterial blood gas collection and resuscitation,respectively, procedures in which considerable bloodcontact may occur.642,655 Differences in observed ad-herence have been reported among occupationalgroups in the same health care facility640 and betweenexperienced and nonexperienced professionals.644 Insurveys of HCWs, self-reported adherence was gener-ally higher than actual adherence found in observa-tional studies. Furthermore, where an observationalcomponent was included with a self-reported survey,self-perceived adherence was often greater than ob-served adherence.656 Among nurses and physicians,increasing years of experience is a negative predictorof adherence.644,650 Education to improve adherenceis the primary intervention that has been studied.Whereas positive changes in knowledge and attitudehave been demonstrated,639,657 no or only limited ac-companying changes in behavior often have beenfound.641,643 Self-reported adherence is higher ingroups that received an educational intervention.629,658
In one study, educational interventions that incorpo-rated videotaping and performance feedback were suc-cessful in improving adherence during the studyperiod, but the long-term effect of such interventionsis not known.653 The use of videotaping also servedto identify system problems (eg, communication andaccess to PPE) that otherwise may not have beenrecognized.
Interest is growing in the use of engineering controlsand facility design concepts for improving adherence.Whereas the introduction of automated sinks wasfound to have a negative impact on consistent adher-ence to handwashing in one study,659 the use of elec-tronic monitoring and voice prompts to remindHCWs to perform hand hygiene and improving acces-sibility to hand hygiene products increased adherenceand contributed to a decrease in HAIs in anotherstudy.660 More information is needed regarding waysin which technology might improve adherence.
Improving adherence to infection control practicesrequires a multifaceted approach that incorporatescontinuous assessment of both the individual and thework environment.558,560 Using several behavioral the-ories, Kretzer and Larson concluded that a single inter-vention (eg, a handwashing campaign or putting upnew posters about transmission precautions) likelywould be ineffective in improving HCWs adherence.661
Improvement requires the organizational leadership tomake prevention an institutional priority and integrateinfection control practices into the organization’s safetyculture.560 A recent review of the literature concludedthat variations in organizational factors (eg, safety cli-mate, policies and procedures, education and training)and individual factors (eg, knowledge, perceptions of
risk, past experience) were determinants of adherenceto infection control guidelines for protection againstSARS and other respiratory pathogens.256
II.B. Surveillance for Health Care-AssociatedInfections
Surveillance is an essential tool for case finding ofsingle patients or clusters of patients who are infected orcolonized with epidemiologically important organisms(eg, susceptible bacteria such as S aureus, S pyogenes[group A streptococcus] or Enterobacter-Klebsiellaspp; MRSA, VRE, and other MDROs; C difficile; RSV;influenza virus) for which transmission-based precau-tions may be required. Surveillance is defined as theongoing systematic collection, analysis, interpretation,and dissemination of data regarding a health-relatedevent for use in public health action to reduce morbidityand mortality and to improve health.662 The work ofIgnaz Semmelweis delineating the role of person-to-person transmission in puerperal sepsis is the earliestexample of the use of surveillance data to reduce trans-mission of infectious agents.663 Surveillance of bothprocess measures and the infection rates to whichthey are linked is important in evaluating the effective-ness of infection prevention efforts and identifyingindications for change.554,664-667
The Study on the Efficacy of Nosocomial InfectionControl (SENIC) found that different combinations ofinfection control practices resulted in reduced rates ofnosocomial surgical site infections, pneumonia,urinary tract infections, and bacteremia in acute carehospitals;565 however, surveillance was the only com-ponent essential for reducing all 4 types of HAIs. Al-though a similar study has not been conducted inother health care settings, a role for surveillance andthe need for novel strategies in LTCFs397,433,668,669 andin home care469-472 have been described. The essentialelements of a surveillance system are (1) standardizeddefinitions, (2) identification of patient populations atrisk for infection, (3) statistical analysis (eg, risk adjust-ment, calculation of rates using appropriate denomin-ators, trend analysis using such methods as statisticalprocess control charts), and (4) feedback of results tothe primary caregivers.670-675 Data gathered throughsurveillance of high-risk populations, device use, pro-cedures, and facility locations (eg, ICUs) are useful indetecting transmission trends.670-672 Identification ofclusters of infections should be followed by a system-atic epidemiologic investigation to determine com-monalities in persons, places, and time and to guideimplementation of interventions and evaluation ofthe effectiveness of those interventions.
Targeted surveillance based on the highest-risk areasor patients has been preferred over facility-wide
S96 Vol. 35 No. 10 Supplement 2 Siegel et al
surveillance for the most effective use of re-sources.672,675 However, for certain epidemiologicallyimportant organisms, surveillance may need to be fa-cility-wide. Surveillance methods will continue toevolve as health care delivery systems change391,676
and user-friendly electronic tools for electronic track-ing and trend analysis become more widely avail-able.673,677,678 Individuals with experience in healthcare epidemiology and infection control should be in-volved in selecting software packages for data aggrega-tion and analysis, to ensure that the need for efficientand accurate HAI surveillance will be met. Effectivesurveillance is increasingly important as legislation re-quiring public reporting of HAI rates is passed andstates work to develop effective systems to supportsuch legislation.679
II.C. Education of Health Care Workers,Patients, and Families
The education and training of HCWs is a prere-quisite for ensuring that policies and procedures forStandard and Transmission-Based Precautions areunderstood and practiced. Understanding the scientificrationale for the precautions will allow HCWs to applyprocedures correctly, as well as to safely modify pre-cautions based on changing requirements, resources,or health care settings.14,654,680-687 One study foundthat the likelihood of HCWs developing SARS wasstrongly associated with less than 2 hours of infectioncontrol training and poor understanding of infectioncontrol procedures.688 Education regarding the impor-tant role of vaccines (eg, influenza, measles, varicella,pertussis, pneumococcal) in protecting HCWs, their pa-tients, and family members can help improve vaccina-tion rates.689-692
Education on the principles and practices for pre-venting transmission of infectious agents should beginduring training in the health professions and be pro-vided to anyone who has an opportunity for contactwith patients or medical equipment (eg, nursing andmedical staff; therapists and technicians, including res-piratory, physical, occupational, radiology, and cardiol-ogy personnel; phlebotomists; housekeeping andmaintenance staff; and students). In health care facili-ties, education and training on Standard and Transmis-sion-Based Precautions are typically provided at thetime of orientation and should be repeated as neces-sary to maintain competency; updated education andtraining are necessary when policies and proceduresare revised or when a special circumstance occurs,such as an outbreak that requires modification ofcurrent practice or adoption of new recommendations.Education and training materials and methods appro-priate to the HCW’s level of responsibility, individual
learning habits, and language needs can improve thelearning experience.657,693-701
Education programs for HCWs have been associatedwith sustained improvement in adherence to best prac-tices and a related decrease in device-associated HAIsin teaching and nonteaching settings638,702 and inmedical and surgical ICUs (Coopersmith, 2002 #2149;Babcock, 2004 #2126; Berenholtz, 2004 #2289; http://www.ihi.org/IHI/Programs/Campaign, #2563). Severalstudies have shown that in addition to targeted educa-tion to improve specific practices, periodic assessmentand feedback of the HCW’s knowledge and adherenceto recommended practices are necessary to achievethe desired changes and identify continuing educationneeds.561,703-707 The effectiveness of this approach forisolation practices has been demonstrated in the con-trol of RSV.116,683
Patients, family members, and visitors can be part-ners in preventing transmission of infections in healthcare settings.9,42,708-710 Information on Standard Pre-cautions, especially hand hygiene, respiratory hy-giene/cough etiquette, vaccination (especially againstinfluenza), and other routine infection prevention strat-egies, may be incorporated into patient informationmaterials provided on admission to the health care fa-cility. Additional information on Transmission-BasedPrecautions is best provided when these precautionsare initiated. Fact sheets, pamphlets, and other printedmaterial may include information on the rationale forthe additional precautions, risks to household mem-bers, room assignment for Transmission-Based Precau-tions purposes, explanation of the use of PPE by HCWs,and directions for use of such equipment by familymembers and visitors. Such information may be partic-ularly helpful in the home environment, where house-hold members often have the primary responsibilityfor adherence to recommended infection control prac-tices. HCWs must be available and prepared to explainthis material and answer questions as needed.
II.D. Hand Hygiene
Hand hygiene has been frequently cited as the singlemost important practice to reduce the transmission ofinfectious agents in health care settings558,711,712 andis an essential element of Standard Precautions. Theterm ‘‘hand hygiene’’ includes both handwashingwith either plain or antiseptic-containing soap and wa-ter and the use of alcohol-based products (gels, rinses,foams) that do not require water. In the absence of vis-ible soiling of hands, approved alcohol-based productsfor hand disinfection are preferred over antimicrobialor plain soap and water because of their superior mi-crobiocidal activity, reduced drying of the skin, andconvenience.558 Improved hand hygiene practices
have been associated with a sustained decrease in theincidence of MRSA and VRE infections primarily inICUs.560,561,713-716 The scientific rationale, indications,methods, and products for hand hygiene have beensummarized in previous publications.558,716
The effectiveness of hand hygiene can be reducedby the type and length of fingernails.558,717,718 Individ-uals wearing artificial nails have been shown to harbormore pathogenic organisms, especially gram-negativebacilli and yeasts, on the nails and in the subungualarea compared with individuals with native nails.719,720
In 2002, the CDC/HICPAC recommended (Category IA)that artificial fingernails and extenders not be wornby HCWs who have contact with high-risk patients(eg, those in ICUs and operating rooms), due to the as-sociation with outbreaks of gram-negative bacillus andcandidal infections as confirmed by molecular typingof isolates.30,31,558,721-724 The need to restrict the wear-ing of artificial fingernails by all HCWs who provide di-rect patient care and those who have contact with otherhigh-risk groups (eg, oncology and cystic fibrosis pa-tients) has not been studied but has been recommendedby some experts.20 Currently, such decisions are at thediscretion of an individual facility’s infection controlprogram. There is less evidence indicating that jewelryaffects the quality of hand hygiene. Although handcontamination with potential pathogens is increasedwith ring-wearing,558,725 no studies have related thispractice to HCW-to-patient transmission of pathogens.
II.E. Personal Protective Equipment for HealthCare Workers
PPE refers to various barriers and respirators usedalone or in combination to protect mucous mem-branes, airways, skin, and clothing from contact withinfectious agents. The choice of PPE is based on the na-ture of the patient interaction and/or the likely mode(s)of transmission. Specific guidance on the use of PPE isprovided in Part III of this guideline. A suggested proce-dure for donning and removing PPE aimed at prevent-ing skin or clothing contamination is presented inFigure 1. Designated containers for used disposableor reusable PPE should be placed in a location conve-nient to the site of removal, to facilitate disposal andcontainment of contaminated materials. Hand hygieneis always the final step after removing and disposing ofPPE. The following sections highlight the primary usesof and criteria for selecting this equipment.
II.E.1. Gloves. Gloves are used to prevent contami-nation of HCW hands when (1) anticipating direct con-tact with blood or body fluids, mucous membranes,nonintact skin and other potentially infectious mate-rial; (2) having direct contact with patients who are col-onized or infected with pathogens transmitted by the
contact route (eg, VRE, MRSA, RSV558,726,727); or (3)handling or touching visibly or potentially contami-nated patient care equipment and environmental sur-faces.72,73,558 Gloves can protect both patients andHCWs from exposure to infectious material that maybe carried on hands.73 The extent to which gloveswill protect HCWs from transmission of bloodbornepathogens (eg, HIV, HBV, HCV) after a needlestick orother puncture that penetrates the glove barrier hasnot yet been determined. Although gloves may reducethe volume of blood on the external surface of a sharpby 46% to 86%,728 the residual blood in the lumen of ahollow-bore needle would not be affected; therefore,the effect on transmission risk is unknown.
Gloves manufactured for health care purposes aresubject to FDA evaluation and clearance.729 Nonsteriledisposable medical gloves made of various materials(eg, latex, vinyl, nitrile) are available for routine patientcare.730 The selection of glove type for nonsurgical useis based on various factors, including the task to be per-formed, anticipated contact with chemicals and che-motherapeutic agents, latex sensitivity, sizing, andfacility policies for creating a latex-free environ-ment.17,731-733 For contact with blood and body fluidsduring nonsurgical patient care, a single pair of glovesgenerally provides adequate barrier protection.733
However, there is considerable variability amonggloves; both the quality of the manufacturing processand type of material influence their barrier effective-ness.734 Whereas there is little difference in the barrierproperties of unused intact gloves,735 studies haveshown repeatedly that vinyl gloves have higher failurerates than latex or nitrile gloves when tested under sim-ulated and actual clinical conditions.730,734-737 For thisreason, either latex or nitrile gloves are preferable forclinical procedures that require manual dexterity orwill involve more than brief patient contact. A facilitymay need to stock gloves in several sizes. Heavier, reus-able utility gloves are indicated for non–patient careactivities, such as handling or cleaning contaminatedequipment or surfaces.11,14,738
During patient care, transmission of infectious orga-nisms can be reduced by adhering to the principles ofworking from ‘‘clean’’ to ‘‘dirty’’ and confining or limit-ing contamination to those surfaces directly needed forpatient care. It may be necessary to change gloves dur-ing the care of a single patient to prevent cross-contam-ination of body sites.558,739 It also may be necessary tochange gloves if the patient interaction also involvestouching portable computer keyboards or other mobileequipment transported from room to room. Discardinggloves between patients is necessary to prevent trans-mission of infectious material. Gloves must not bewashed for subsequent reuse, because microorganismscannot be removed reliably from glove surfaces, and
S98 Vol. 35 No. 10 Supplement 2 Siegel et al
Fig 1. Example of safe donning and removal of PPE.
continued glove integrity cannot be ensured. Further-more, glove reuse has been associated with transmis-sion of MRSA and gram-negative bacilli.740-742
When gloves are worn in combination with otherPPE, they are put on last. Gloves that fit snugly aroundthe wrist are preferred for use with an isolation gown,because they will cover the gown cuff and provide amore reliable continuous barrier for the arms, wrists,and hands. Proper glove removal will prevent handcontamination (Fig 1). Hand hygiene after glove re-moval further ensures that the hands will not carry po-tentially infectious material that might have penetratedthrough unrecognized tears or that could have contam-inated the hands during glove removal.558,727,740
II.E.2. Isolation Gowns. Isolation gowns are used asspecified by Standard and Transmission-Based Precau-tions to protect the HCW’s arms and exposed bodyareas and prevent contamination of clothing with
blood, body fluids, and other potentially infectious ma-terial.24,88,261,743-745 The need for and the type of isola-tion gown selected is based on the nature of the patientinteraction, including the anticipated degree of contactwith infectious material and potential for blood andbody fluid penetration of the barrier. The wearing ofisolation gowns and other protective apparel is man-dated by the Occupational Safety and Health Adminis-tration’s (OSHA) Bloodborne Pathogens Standard.738
Clinical and laboratory coats or jackets worn over per-sonal clothing for comfort and/or purposes of identityare not considered PPE.
When applying Standard Precautions, an isolationgown is worn only if contact with blood or body fluidis anticipated. However, when Contact Precautionsare used (ie, to prevent transmission of an infectiousagent that is not interrupted by Standard Precautionsalone and is associated with environmental
Siegel et al December 2007 S99
contamination), donning of both gown and gloves onroom entry is indicated, to prevent unintentional con-tact with contaminated environmental surfaces.54,72,
73,88 The routine donning of isolation gowns on entryinto an ICU or other high-risk area does not preventor influence potential colonization or infection ofpatients in those areas, however.364,746-749
Isolation gowns are always worn in combinationwith gloves, and with other PPE when indicated.Gowns are usually the first piece of PPE to be donned.Full coverage of the arms and body front, from neck tothe mid-thigh or below, will ensure protection of cloth-ing and exposed upper body areas. Several gown sizesshould be available in a health care facility to ensureappropriate coverage for staff members. Isolationgowns should be removed before leaving the patientcare area to prevent possible contamination of the en-vironment outside the patient’s room. Isolation gownsshould be removed in a manner that prevents contam-ination of clothing or skin (Fig 1); the outer, ‘‘contami-nated’’ side of the gown is turned inward and rolledinto a bundle, and then discarded into a designatedcontainer for waste or linen to contain contamination.
II.E.3. Face Protection: Masks, Goggles, and FaceShields.
II.E.3.a. Masks. Masks are used for 3 primary pur-poses in health care settings: (1) placed on HCWs toprotect them from contact with infectious materialfrom patients (eg, respiratory secretions and sprays ofblood or body fluids), consistent with Standard Precau-tions and Droplet Precautions; (2) placed on HCWs en-gaged in procedures requiring sterile technique, toprotect patients from exposure to infectious agents car-ried in the HCW’s mouth or nose; and (3) placed oncoughing patients to limit potential dissemination ofinfectious respiratory secretions from the patient toothers (ie, respiratory hygiene/cough etiquette). Masksmay be used in combination with goggles to protectthe mouth, nose, and eyes, or, alternatively, a faceshield may be used instead of a mask and goggles toprovide more complete protection for the face, as dis-cussed below. Masks should not be confused with par-ticulate respirators used to prevent inhalation of smallparticles that may contain infectious agents transmit-ted through the airborne route, as described below.
The mucous membranes of the mouth, nose, andeyes are susceptible portals of entry for infectiousagents; other skin surfaces also may be portals if skinintegrity is compromised (by, eg, acne, dermatitis).66,
750-753 Therefore, use of PPE to protect these body sitesis an important component of Standard Precautions.The protective effect of masks for exposed HCWs hasbeen demonstrated previously.93,113,754,755 Proceduresthat generate splashes or sprays of blood, body fluids,secretions, or excretions (eg, endotracheal suctioning,
bronchoscopy, invasive vascular procedures) requireeither a face shield (disposable or reusable) or a maskand goggles.93-96,113,115,261,738,756 The wearing ofmasks, eye protection, and face shields in specified cir-cumstances when blood or body fluid exposure islikely is mandated by OSHA’s Bloodborne PathogensStandard.738 Appropriate PPE should be selected basedon the anticipated level of exposure.
Two mask types are available for use in health caresettings: surgical masks that are cleared by the FDAand required to have fluid-resistant properties, and pro-cedure or isolation masks.757,#2688 To date, no studiescomparing mask types to determine whether onemask type provides better protection than anotherhave been published. Because procedure/isolationmasks are not regulated by the FDA, they may bemore variable in terms of quality and performancethan surgical masks. Masks come in various shapes(eg, molded and nonmolded), sizes, filtration efficiency,and method of attachment (eg, ties, elastic, ear loops).Health care facilities may find that different types ofmasks are needed to meet individual HCW needs.
II.E.3.b. Goggles and Face Shields. Guidance on eyeprotection for infection control has been published.758
The eye protection chosen for specific work situations(eg, goggles or face shield) depends on the circumstancesof exposure, other PPE used, and personal vision needs.Personal eyeglasses and contact lenses are not consid-ered adequate eye protection (see http://www.cdc.gov/niosh/topics/eye/eye-infectious.html). NIOSH guidelinesspecify that eye protection must be comfortable, allowfor sufficient peripheral vision, and adjustable to ensurea secure fit. A health care facility may need to provideseveral different types, styles, and sizes of eye protectionequipment. Indirectly vented goggles with a manufac-turer’s antifog coating may provide the most reliablepractical eye protection from splashes, sprays, and respi-ratory droplets from multiple angles. Newer styles ofgoggles may provide better indirect airflow propertiesto reduce fogging, as well as better peripheral visionand more size options for fitting goggles to differentworkers. Many styles of goggles fit adequately over pre-scription glasses with minimal gaps. Although effectiveas eye protection, goggles do not provide splash or sprayprotection to other parts of the face.
The role of goggles in addition to a mask in pre-venting exposure to infectious agents transmittedthrough respiratory droplets has been studied onlyfor RSV. Reports published in the mid-1980s demon-strated that eye protection reduced occupationaltransmission of RSV.759,760 Whether this was due tothe prevention hand–eye contact or the preventionof respiratory droplet–eye contact has not been deter-mined. However, subsequent studies demonstratedthat RSV transmission is effectively prevented by
adherence to Standard Precautions plus Contact Pre-cautions and that routine use of goggles is not neces-sary for this virus.24,116,117,683,761 It is important toremind HCWs that even if Droplet Precautions arenot recommended for a specific respiratory tract path-ogen, protection for the eyes, nose, and mouth using amask and goggles or a face shield alone is necessarywhen a splash or spray of any respiratory secretionsor other body fluids is likely to occur, as defined inStandard Precautions.
Disposable or nondisposable face shields may beused as an alternative to goggles.758 Compared withgoggles, a face shield can provide protection to otherfacial areas besides the eyes. Face shields extendingfrom the chin to crown provide better face and eye pro-tection from splashes and sprays; face shields thatwrap around the sides may reduce splashes aroundthe edge of the shield.
Removal of a face shield, goggles, and mask can beperformed safely after gloves have been removed andhand hygiene performed. The ties, earpieces, and/orheadband used to secure the equipment to the headare considered ‘‘clean’’ and thus safe to touch withbare hands. The front of a mask, goggles, and faceshield are considered contaminated (Fig 1).
II.E.4. Respiratory Protection. The subject of respi-ratory protection as it applies to preventing transmis-sion of airborne infectious agents, including the needfor and frequency of fit testing is under scientific re-view and was the subject of a 2004 CDC workshop.762
Respiratory protection currently requires the use of arespirator with N95 or higher-level filtration to preventinhalation of infectious particles. Information aboutrespirators and respiratory protection programs issummarized in the Guideline for Preventing Transmis-sion of Mycobacterium tuberculosis in Health CareSettings.12
Respiratory protection is broadly regulated by OSHAunder the general industry standard for respiratoryprotection (29 CFR 1910.134),763 which requires thatUS employers in all employment settings implementa program to protect employees from inhalation oftoxic materials. OSHA program components includemedical clearance to wear a respirator; provision anduse of appropriate respirators, including fit-testedNIOSH-certified N95 and higher-level particulate filter-ing respirators; education on respirator use, and peri-odic reevaluation of the respiratory protectionprogram. When selecting particulate respirators,models with inherently good fit characteristics (ie,those expected to provide protection factors of $
10% to 95% of wearers) are preferred and theoreticallycould preclude the need for fit testing.764,765 Issues per-taining to respiratory protection remain the subject ofongoing debate. Information on various types of
respirators is available at http://www.cdc.gov/niosh/npptl/respirators/respsars.html and in several previ-ously published studies.764,766,767 A user-seal check(formerly called a ‘‘fit check’’) should be performedby the wearer of a respirator each time that the respira-tor is donned, to minimize air leakage around the facepiece.768 The optimal frequency of fit testing has notbeen determined; retesting may be indicated if thereis a change in wearer’s facial features, onset of a med-ical condition that would affect respiratory function inthe wearer, or a change in the model or size of the res-pirator that was initially assigned.12
Respiratory protection was first recommended forprotection of US HCWs from exposure to M tuberculo-sis in 1989. That recommendation has been main-tained in 2 successive revisions of the Guidelines forPrevention of Transmission of Tuberculosis in Hospitalsand Other Health Care Settings.12,126 The incrementalbenefit from respirator use, in addition to administra-tive and engineering controls (ie, AIIRs, early recogni-tion of patients likely to have tuberculosis andprompt placement in an AIIR, and maintenance of a pa-tient with suspected tuberculosis in an AIIR until nolonger infectious), for preventing transmission of air-borne infectious agents (eg, M tuberculosis) remainsundetermined. Although some studies have demon-strated effective prevention of M tuberculosis transmis-sion in hospitals in which surgical masks instead ofrespirators were used in conjunction with other admin-istrative and engineering controls.636,769,770 the CDCcurrently recommends N95 or higher-level respiratorsfor personnel exposed to patients with suspected orconfirmed tuberculosis. Currently, this recommenda-tion also holds for other diseases that could be trans-mitted through the airborne route, including SARS261
and smallpox,108,129,771 until inhalational transmissionis better defined or health care-specific PPE more suit-able for preventing infection is developed. Wearing ofrespirators is also currently recommended during theperformance of aerosol-generating procedures (eg, in-tubation, bronchoscopy, suctioning) in patients withSARS-CoV infection, avian influenza, and pandemic in-fluenza (see Appendix A).
Although Airborne Precautions are recommendedfor preventing airborne transmission of measles andvaricella-zoster viruses, no data are available on whichto base a recommendation for respiratory protection toprotect susceptible personnel against these 2 infec-tions. Transmission of varicella-zoster virus has beenprevented among pediatric patients using negative-pressure isolation alone.772 Whether respiratory pro-tection (ie, wearing a particulate respirator) willenhance protection from these viruses has not yet beenstudied. Because most HCWs have natural or acquiredimmunity to these viruses, only immune personnel
generally care for patients with these infections.773-776
Although there is no evidence suggesting that masksare not adequate to protect HCWs in these settings,for purposes of consistency and simplicity, or becauseof difficulties in ascertaining immunity, some facilitiesmay require the use of respirators for entry into allAIIRs, regardless of the specific infectious agent present.
Procedures for safe removal of respirators are pro-vided in Figure 1. In some health care settings, particu-late respirators used to provide care for patients with Mtuberculosis are reused by the same HCW. This is an ac-ceptable practice providing that the respirator is notdamaged or soiled, the fit is not compromised by achange in shape, and the respirator has not been con-taminated with blood or body fluids. No data are avail-able on which to base a recommendation regardingthe length of time that a respirator may be safely reused.
II.F. Safe Work Practices to Prevent Health CareWorker Exposure to Bloodborne Pathogens
II.F.1. Prevention of Needlesticks and OtherSharps-Related Injuries. Injuries due to needles andother sharps have been associated with transmissionof HBV, HCV, and HIV to HCWs.777,778 The preventionof sharps injuries has always been an essential elementof Universal Precautions and is now an aspect of Stan-dard Precautions.1,779 These include measures to han-dle needles and other sharp devices in a manner thatwill prevent injury to the user and to others who mayencounter the device during or after a procedure. Thesemeasures apply to routine patient care and do not ad-dress the prevention of sharps injuries and other bloodexposures during surgical and other invasive proce-dures addressed elsewhere.780-784
Since 1991, when OSHA first issued its BloodbornePathogens Standard to protect HCWs from blood expo-sure, the focus of regulatory and legislative activity hasbeen on implementing a hierarchy of control mea-sures. This has included focusing attention on remov-ing sharps hazards through the development and useof engineering controls. The federal Needlestick Safetyand Prevention Act, signed into law in November 2000,authorized OSHA’s revision of its Bloodborne Patho-gens Standard to more explicitly require the use ofsafety-engineered sharps devices.785 The CDC has pro-vided guidance on sharps injury prevention,786,787 in-cluding guidelines for the design, implementationand evaluation of a comprehensive sharps injury pre-vention program.788
II.F.2. Prevention of Mucous Membrane Contact.Exposure of mucous membranes of the eyes, nose,and mouth to blood and body fluids has been associ-ated with the transmission of bloodborne viruses andother infectious agents to HCWs.66,751,753,778 The
prevention of mucous membrane exposures has al-ways been an element of Universal Precautions andis now an element of Standard Precautions for routinepatient care1,752 and is subject to OSHA bloodbornepathogen regulations. Safe work practices, in additionto wearing PPE, are designed to protect mucous mem-branes and nonintact skin from contact with poten-tially infectious material. These include keepingcontaminated gloved and ungloved hands from touch-ing the mouth, nose, eyes, or face and positioning pa-tients to direct sprays and splatter away from thecaregiver’s face. Careful placement of PPE before pa-tient contact will help avoid the need to make adjust-ments to PPE and prevent possible face or mucousmembrane contamination during use.
In areas where the need for resuscitation is unpre-dictable, mouthpieces, pocket resuscitation maskswith 1-way valves, and other ventilation devices pro-vide an alternative to mouth-to-mouth resuscitation,preventing exposure of the caregiver’s nose and mouthto oral and respiratory fluids during the procedure.
II.F.2.a. Precautions During Aerosol-GeneratingProcedures. The performance of procedures that cangenerate small-particle aerosols (aerosol-generatingprocedures), such as bronchoscopy, endotracheal intu-bation, and open suctioning of the respiratory tract,have been associated with transmission of infectiousagents to HCWs, including M tuberculosis,789 SARS-CoV,93,94,98 and N meningitidis.95 Protection of theeyes, nose, and mouth, in addition to gown and gloves,is recommended during performance of these proce-dures in accordance with Standard Precautions. Theuse of a particulate respirator is recommended duringaerosol-generating procedures when the aerosol islikely to contain M tuberculosis, SARS-CoV, or avianor pandemic influenza viruses.
II.G. Patient Placement
II.G.1. Hospitals and Long-Term Care Facilities. Op-tions for patient placement include single-patientrooms, 2-patient rooms, and multibed wards. Of these,single-patient rooms are preferred when transmissionof an infectious agent is of concern. Although somestudies have failed to demonstrate the efficacy ofsingle-patient rooms in preventing HAIs,790 other pub-lished studies, including one commissioned by the AIAand the Facility Guidelines Institute, have documenteda beneficial relationship between private rooms andreduced infectious and noninfectious adverse patientoutcomes.791,792 The AIA notes that private rooms arethe trend in hospital planning and design. However,most hospitals and LTCFs have multibed rooms andmust consider many competing priorities when deter-mining the appropriate room placement for patients
S102 Vol. 35 No. 10 Supplement 2 Siegel et al
(eg, reason for admission; patient characteristics, suchas age, gender, and mental status; staffing needs; familyrequests; psychosocial factors; reimbursement con-cerns). In the absence of obvious infectious diseasesthat require specified airborne infection isolationrooms (eg, tuberculosis, SARS, chickenpox), the riskof transmission of infectious agents is not always con-sidered when making placement decisions.
When only a limited number of single-patient roomsis available, it is prudent to prioritize room assignmentsfor those patients with conditions that facilitate trans-mission of infectious material to other patients (eg,draining wounds, stool incontinence, uncontained se-cretions) and those at increased risk of acquisitionand adverse outcomes resulting from HAIs (due to,eg, immunosuppression, open wounds, indwellingcatheters, anticipated prolonged length of stay, totaldependence on HCWs for activities of dailyliving).15,24,43,429,793,794
Single-patient rooms are always indicated for pa-tients placed on Airborne Precautions in a PE and arepreferred for patients requiring Contact or Droplet Pre-cautions.23,24,409,434,795,796 During a suspected orproven outbreak caused by a pathogen whose reservoiris the gastrointestinal tract, the use of single-patientrooms with private bathrooms limits opportunitiesfor transmission, especially when the colonized or in-fected patient has poor personal hygiene habits or fecalincontinence, or cannot be expected to assist in main-taining procedures that prevent transmission of micro-organisms (eg, infants, children, and patients withaltered mental status or developmental delay). In theabsence of continued transmission, it is not necessaryto provide a private bathroom for patients colonized orinfected with enteric pathogens as long as personal hy-giene practices and Standard Precautions (especiallyhand hygiene and appropriate environmental clean-ing) are maintained. Assignment of a dedicated com-mode to a patient, and cleaning and disinfectingfixtures and equipment that may have fecal contami-nation (eg, bathrooms, commodes,797 scales used forweighing diapers) and the adjacent surfaces with ap-propriate agents may be especially important when asingle-patient room cannot be assigned, because envi-ronmental contamination with intestinal tract patho-gens is likely from both continent and incontinentpatients.54,798 The results of several studies that inves-tigated the benefit of a single-patient room in prevent-ing transmission of C difficile were inconclusive.167,799-
801 Some studies have shown that being in the sameroom with a colonized or infected patient is not neces-sarily a risk factor for transmission;790,802-804 however,for children, the risk of health care–associated diarrheais increased with the increased number of patientsper room.805 These findings demonstrate that patient
factors are important determinants of infection trans-mission risks. The need for a single-patient roomand/or private bathroom for any patient is best deter-mined on a case-by-case basis.
Cohorting is the practice of grouping together pa-tients who are colonized or infected with the same or-ganism to confine their care to a single area andprevent contact with other patients. Cohorts are createdbased on clinical diagnosis, microbiologic confirmation(when available), epidemiology, and mode of transmis-sion of the infectious agent. Avoiding placing severelyimmunosuppressed patients in rooms with other pa-tients is generally preferred. Cohorting has been exten-sively used for managing outbreaks of MDROs,including MRSA,22, 806 VRE,637,807,808 MDR-ESBL,809
P aeruginosa,29 MSSA,810 RSV,811,812 adenovirus kerato-conjunctivitis,813 rotavirus,814 and SARS.815 Modelingstudies provide additional support for cohorting pa-tients to control outbreaks;816-818 however, cohortingoften is implemented only after routine infection con-trol measures have failed to control an outbreak.
Assigning or cohorting HCWs to care only for pa-tients infected or colonized with a single target patho-gen limits further transmission of the target pathogento uninfected patients,739,818 but is difficult to achievein the face of current staffing shortages in hospitals582
and residential health care sites.819-821 However, co-horting of HCWs may be beneficial when transmissioncontinues after implementing routine infection controlmeasures and creating patient cohorts.
During periods when RSV, human metapneumovi-rus,822 parainfluenza, influenza, other respiratory vi-ruses,823 and rotavirus are circulating in thecommunity, cohorting based on the presenting clinicalsyndrome is often a priority in facilities that care for in-fants and young children.824 For example, during therespiratory virus season, infants may be cohortedbased solely on the clinical diagnosis of bronchiolitis,due to the logistical difficulties and costs associatedwith requiring microbiologic confirmation beforeroom placement and the predominance of RSV duringmost of the season. However, when available, single-pa-tient rooms are always preferred, because a commonclinical presentation (eg, bronchiolitis), can be causedby more than 1 infectious agent.822,823,825 Furthermore,the inability of infants and children to contain bodyfluids, and the close physical contact associated withtheir care, increases the risk of infection transmissionfor patients and personnel in this setting.24,794
II.G.2. Ambulatory Care Settings. Patients activelyinfected with or incubating transmissible infectiousdiseases are frequently seen in ambulatory settings (eg,outpatient clinics, physicians’ offices, emergency de-partments) and potentially expose HCWs and other pa-tients, family members, and visitors.21,34,127,135,142,826
Siegel et al December 2007 S103
In response to the global outbreak of SARS in 2003 andin preparation for pandemic influenza, HCWs working inoutpatient settings are urged to implement source con-tainment measures (eg, asking coughing patients towear a surgical mask or cover coughing with tissues)to prevent transmission of respiratory infections, be-ginning at the initial patient encounter,9,261,827 as de-scribed in Section III.A.1.a. Signs can be posted at thefacility’s entrance or at the reception or registrationdesk requesting that the patient or individuals accom-panying the patient promptly inform the receptionistof any symptoms of respiratory infection (eg, cough, flu-like illness, increased production of respiratory secre-tions). The presence of diarrhea, skin rash, or knownor suspected exposure to a transmissible disease (eg,measles, pertussis, chickenpox, tuberculosis) also couldbe added. Prompt placement of a potentially infectiouspatient in an examination room limits the number of ex-posed individuals in the common waiting area.
In waiting areas, maintaining a distance betweensymptomatic and nonsymptomatic patients (eg, . 3feet), in addition to source control measures, may limitexposures. However, infections transmitted throughthe airborne route (eg, M tuberculosis, measles, chicken-pox) require additional precautions.12,125,828 Patientssuspected of having such an infection can wear a surgi-cal mask for source containment, if tolerated, andshould be placed in an examination room (preferablyan AIIR) as soon as possible. If this is not possible, thenhaving the patient wear a mask and segregating the pa-tient from other patients in the waiting area will reducethe risk of exposing others. Because the person(s) ac-companying the patient also may be infectious, applica-tion of the same infection control precautions maybe extended to these persons if they are sympto-matic.21,251,829 Family members accompanying chil-dren admitted with suspected M tuberculosis havebeen found to have unsuspected pulmonary tuberculo-sis with cavitary lesions, even when asymptomatic.42,830
Patients with underlying conditions that increasetheir susceptibility to infection (eg, immunocompro-mised status43,44 or cystic fibrosis20) require special ef-forts to protect them from exposure to infected patientsin common waiting areas. Informing the receptionist oftheir infection risk on arrival allows appropriate stepsto further protect these patients from infection. Insome cystic fibrosis clinics, to avoid exposure to otherpatients who could be colonized with B cepacia, pa-tients have been given beepers on registration so thatthey may leave the area and receive notification to re-turn when an examination room becomes available.831
II.G.3. Home Care. In home care, patient placementconcerns focus on protecting others in the home fromexposure to an infectious household member. Forindividuals who are especially vulnerable to adverse
outcomes associated with certain infections, it maybe beneficial to either remove them from the homeor segregate them within the home. Persons who arenot part of the household may need to be prohibitedfrom visiting during the period of infectivity. For exam-ple, in a situation where a patient with pulmonary tu-berculosis is contagious and being cared for at home,very young children (age under 4 years)832 and immu-nocompromised persons who have not yet been in-fected should be removed or excluded from thehousehold. During the SARS outbreak of 2003, segrega-tion of infected persons during the communicablephase of the illness was found to be beneficial in pre-venting household transmission.249,833
II.H. Transport of Patients
Several principles guide the transport of patients re-quiring Transmission-Based Precautions. In the inpatientand residential settings, these include the following:
1. Limiting transport of such patients to essentialpurposes, such as diagnostic and therapeutic proce-dures that cannot be performed in the patient’s room.
2. When transport is necessary, applying appropri-ate barriers on the patient (eg, mask, gown, wrappingin sheets or use of impervious dressings to cover the af-fected areas) when infectious skin lesions or drainageare present, consistent with the route and risk oftransmission.
3. Notifying HCWs in the receiving area of the pa-tient’s impending arrival and of the necessary precau-tions to prevent transmission.
4. For patients being transported outside the facility,informing the receiving facility and the medi-van oremergency vehicle personnel in advance about thetype of Transmission-Based Precautions being used.
For tuberculosis, additional precautions may beneeded in a small shared air space, such as in anambulance.12
II.I. Environmental Measures
Cleaning and disinfecting noncritical surfaces in pa-tient care areas is an aspect of Standard Precautions. Ingeneral, these procedures do not need to be changedfor patients on Transmission-Based Precautions. Thecleaning and disinfection of all patient care areas is im-portant for frequently touched surfaces, especiallythose closest to the patient, which are most likely tobe contaminated (eg, bedrails, bedside tables, com-modes, doorknobs, sinks, surfaces and equipment inclose proximity to the patient).11,72,73,834 The fre-quency or intensity of cleaning may need to bechanged, based on the patient’s level of hygiene andthe degree of environmental contamination and forcertain infectious agents with reservoirs in the
S104 Vol. 35 No. 10 Supplement 2 Siegel et al
intestinal tract.54 This may be particularly important inLTCFs and pediatric facilities, where patients with stooland urine incontinence are encountered more fre-quently. In addition, increased frequency of cleaningmay be needed in a PE to minimize dust accumula-tion.11 Special recommendations for cleaning and dis-infecting environmental surfaces in dialysis centershave been published previously.18 In all health care set-tings, administrative, staffing, and scheduling activitiesshould prioritize the proper cleaning and disinfectionof surfaces that could be implicated in transmission.During a suspected or proven outbreak in which an en-vironmental reservoir is suspected, routine cleaningprocedures should be reviewed, and the need for addi-tional trained cleaning staff should be assessed. Adher-ence should be monitored and reinforced to promoteconsistent and correct cleaning.
US Environmental Protection Agency–registered dis-infectants or detergents/disinfectants that best meetthe overall needs of the health care facility for routinecleaning and disinfection should be selected.11,835 Ingeneral, use of the existing facility detergent/disinfec-tant according to the manufacturer’s recommendationsfor amount, dilution, and contact time is sufficient toremove pathogens from surfaces of rooms where colo-nized or infected individuals were housed. This in-cludes those pathogens that are resistant to multipleclasses of antimicrobial agents (eg, C difficile, VRE,MRSA, MDR-GNB11,24,88,434,745,795,836). Most often, en-vironmental reservoirs of pathogens during outbreaksare related to a failure to follow recommended proce-dures for cleaning and disinfection, rather than to thespecific cleaning and disinfectant agents used.837-840
Certain pathogens (eg, rotavirus, noroviruses, C diffi-cile) may be resistant to some routinely used hospitaldisinfectants.274,291,841-846 The role of specific disinfec-tants in limiting transmission of rotavirus has beendemonstrated experimentally.841 Also, because C diffi-cile may display increased levels of spore productionwhen exposed to non–chlorine-based cleaning agents,and because these spores are more resistant than veg-etative cells to commonly used surface disinfectants,some investigators have recommended the use of a1:10 dilution of 5.25% sodium hypochlorite (house-hold bleach) and water for routine environmental dis-infection of rooms of patients with C difficile whenthere is continued transmission.843,847 One studyfound an association between the use of a hypochloritesolution and decreased rates of C difficile infections.846
The need to change disinfectants based on the pres-ence of these organisms can be determined in consul-tation with the infection control committee.11,846,847
Detailed recommendations for disinfection and ster-ilization of surfaces and medical equipment that havebeen in contact with prion-containing tissue or high
risk body fluids, and for cleaning of blood and bodysubstance spills, are available in the Guidelines for En-vironmental Infection Control in Health Care Facilities11
and in the Guideline for Disinfection and Sterilization.847
II.J. Patient Care Equipment and Instruments/Devices
Medical equipment and instruments/devices mustbe cleaned and maintained according to the manufac-turers’ instructions to prevent patient-to-patient trans-mission of infectious agents.86,87,324,848 Cleaning toremove organic material always must precede high-level disinfection and sterilization of critical and semi-critical instruments and devices, because residual pro-teinacous material reduces the effectiveness of thedisinfection and sterilization processes.835,847 Noncrit-ical equipment, such as commodes, intravenouspumps, and ventilators, must be thoroughly cleanedand disinfected before being used on another patient.All such equipment and devices should be handled ina manner that will prevent HCW and environmentalcontact with potentially infectious material. It is impor-tant to include computers and personal digital assis-tants used in patient care in policies for cleaning anddisinfection of noncritical items. The literature on con-tamination of computers with pathogens has beensummarized,849 and 2 reports have linked computercontamination to colonization and infections in pa-tients.850,851 Although keyboard covers and washablekeyboards that can be easily disinfected are available,the infection control benefit of these items and theiroptimal management have not yet been determined.
In all health care settings, providing patients who areon Transmission-Based Precautions with dedicatednoncritical medical equipment (eg, stethoscope, bloodpressure cuff, electronic thermometer) has proven ben-eficial for preventing transmission.74,89,739,852,853 Whenthis is not possible, disinfection of this equipment aftereach use is recommended. Other previously publishedguidelines should be consulted for detailed guidancein developing specific protocols for cleaning and reproc-essing medical equipment and patient care items in bothroutine and special circumstances.11,14,18,20,739,835,847
In home care, it is preferable to remove visible bloodor body fluids from durable medical equipment beforeit leaves the home. Equipment can be cleaned onsiteusing a detergent/disinfectant and, when possible,should be placed in a plastic bag for transport to the re-processing location.20,738
II.K. Textiles and Laundry
Although soiled textiles, including bedding, towels,and patient or resident clothing, may be contaminated
Siegel et al December 2007 S105
with pathogenic microorganisms, the risk of diseasetransmission is negligible if these textiles are handled,transported, and laundered in a safe manner.11,854,855
Key principles for handling soiled laundry are (1)avoiding shaking the items or handling them in anyway that may aerosolize infectious agents, (2) avoidingcontact of one’s body and personal clothing with thesoiled items being handled, and (3) containing soileditems in a laundry bag or designated bin. If a laundrychute is used, it must be maintained to minimize dis-persion of aerosols from contaminated items.11
Methods of handling, transporting, and launderingsoiled textiles are determined by organizational policyand any applicable regulations;738 guidance is providedin the Guidelines for Environmental Infection Control inHealth Care Facilities.11 Rather than rigid rules and reg-ulations, hygienic and common sense storage and pro-cessing of clean textiles is recommended.11,856 Whenlaundering is done outside of a health care facility,the clean items must be packaged or completely cov-ered and placed in an enclosed space during transportto prevent contamination with outside air or construc-tion dust that could contain infectious fungal sporesthat pose a risk for immunocompromised patients.11
Institutions are required to launder garments used asPPE and uniforms visibly soiled with blood or infectivematerial.738 Little data exist on the safety of home laun-dering of HCW uniforms, but no increase in infectionrates was observed in the one published study,857 andno pathogens were recovered from home- or hospi-tal-laundered scrubs in another study.858 In the home,textiles and laundry from patients with potentiallytransmissible infectious pathogens do not require spe-cial handling or separate laundering and may bewashed with warm water and detergent.11,857,858
II.L. Solid Waste
The management of solid waste emanating from thehealth care environment is subject to federal and stateregulations for medical and nonmedical waste.859,860
No additional precautions are needed for nonmedicalsolid waste removed from rooms of patients on Trans-mission-Based Precautions. Solid waste may be con-tained in a single bag of sufficient strength.861
II.M. Dishware and Eating Utensils
The combination of hot water and detergents used indishwashers is sufficient to decontaminate dishwareand eating utensils. Therefore, no special precautionsare needed for dishware (eg, dishes, glasses, cups) or eat-ing utensils. Reusable dishware and utensils may beused for patients requiring Transmission-Based Precau-tions. In the home and other communal settings, eatingutensils and drinking vessels should not be shared,
consistent with principles of good personal hygieneand to help prevent transmission of respiratory viruses,herpes simplex virus, and infectious agents that infectthe gastrointestinal tract and are transmitted by the fe-cal/oral route (eg, hepatitis A virus, noroviruses). If ade-quate resources for cleaning utensils and dishes are notavailable, then disposable products may be used.
II.N. Adjunctive Measures
Important adjunctive measures that are not consid-ered primary components of programs to preventtransmission of infectious agents but nonetheless im-prove the effectiveness of such programs include (1)antimicrobial management programs, (2) postexposurechemoprophylaxis with antiviral or antibacterialagents, (3) vaccines used both for pre-exposure andpostexposure prevention, and (4) screening and re-stricting visitors with signs of transmissible infections.Detailed discussion of judicious use of antimicrobialagents is beyond the scope of this document; however,this topic has been addressed in a previous CDCguideline (http://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline2006.pdf).
II.N.1. Chemoprophylaxis. Antimicrobial agentsand topical antiseptics may be used to prevent infec-tion and potential outbreaks of selected agents. Infec-tions for which postexposure chemoprophylaxis isrecommended under defined conditions include B per-tussis,17,862 N meningitides,863 B anthracis after envi-ronmental exposure to aeosolizable material,864
influenza virus,610 HIV,865 and group A streptococ-cus.160 Orally administered antimicrobials also maybe used under defined circumstances for MRSA decol-onization of patients or HCWs.866
Another form of chemoprophylaxis involves the useof topical antiseptic agents. For example, triple dye isroutinely used on the umbilical cords of term new-borns to reduce the risk of colonization, skin infec-tions, and omphalitis caused by S aureus, includingMRSA, and group A streptococcus.867,868 Extension ofthe use of triple dye to low birth weight infants in aNICU was one component of a program that controlleda long-standing MRSA outbreak.22 Topical antiseptics(eg, mupirocin) also are used for decolonization ofHCWs or selected patients colonized with MRSA, as dis-cussed in the MDRO guideline866,869-872
II.N.2. Immunoprophylaxis. Certain immunizationsrecommended for susceptible HCWs have decreasedthe risk of infection and the potential for transmissionin health care facilities.17,873 The OSHA mandate requir-ing employers to offer HBV vaccination to HCWs hasplayed a substantial role in the sharp decline in inci-dence of occupational HBV infection.777,874 The routineadministration of varicella vaccine to HCWs has
decreased the need to place susceptible HCWs onadministrative leave after exposure to patients withvaricella.774 In addition, reports of health care–associ-ated transmission of rubella in obstetric clinics33,875
and measles in acute care settings34 demonstrate theimportance of immunization of susceptible HCWsagainst childhood diseases. Many states have require-ments for vaccination of HCWs for measles and rubellain the absence of evidence of immunity. Annual influ-enza vaccine campaigns targeted at patients andHCWs in LTCFs and acute care settings have been instru-mental in preventing or limiting institutional outbreaks;consequently, increasing attention is being directedtoward improving influenza vaccination rates inHCWs.35,610,689,876-878
Transmission of B pertussis in health care facilitieshas been associated with large and costly outbreaksthat include both HCWs and patients.17,36,41,100,682,826,
879,880 HCWs in close contact with infants with pertus-sis are at particularly high risk because of waningimmunity and, until 2005, the absence of a vaccine ap-propriate for adults. But 2 acellular pertussis vaccineswere licensed in the United States in 2005, 1 for usein individuals age 11 to 18 years and the other for usein those age 10 to 64 years.881 Current AdvisoryCommittee on Immunization Practices provisional rec-ommendations include immunization of adolescentsand adults, especially those in contact with infantsunder age 12 months and HCWs with direct patientcontact.882,883
Immunization of children and adults will help pre-vent the introduction of vaccine-preventable diseasesinto health care settings. The recommended immuni-zation schedule for children is published annually inthe January issues of the Morbidity and MortalityWeekly Report, with interim updates as needed.884,885
An adult immunization schedule also is available forhealthy adults and those with special immunizationneeds due to high-risk medical conditions.886
Some vaccines are also used for postexposure pro-phylaxis of susceptible individuals, including vari-cella,887 influenza,610 hepatitis B,777 and smallpox225
vaccines.17,873 In the future, administration of a newlydeveloped S aureus conjugate vaccine (still under in-vestigation) to selected patients may provide a novelmethod of preventing health care–associated S aureus(including MRSA) infections in high-risk groups (eg, he-modialysis patients and candidates for selected surgi-cal procedures).888, 889
Immune globulin preparations also are used forpostexposure prophylaxis of certain infectious agentsunder specified circumstances (eg, varicella-zoster vi-rus, HBV, rabies, measles and hepatitis A virus17,832,873).The RSV monoclonal antibody preparation palivizu-mab may have contributed to controlling a nosocomial
outbreak of RSV in one NICU, but there is insufficientevidence to support a routine recommendation for itsuse in this setting.890
II.N.3. Management of Visitors.II.N.3.a. Visitors as Sources of Infection. Visitors
have been identified as the source of several types ofHAIs (eg, pertussis,40,41M tuberculosis,42,891 influenza andother respiratory viruses24,43,44,372 and SARS21,252-254).Effective methods for visitor screening in health caresettings have not yet been studied, however. Visitorscreening is especially important during communityoutbreaks of infectious diseases and for high-risk pa-tient units. Sibling visits are often encouraged in birth-ing centers, postpartum rooms, pediatric inpatientunits, PICUs, and residential settings for children; inhospital settings, a child visitor should visit only his orher own sibling. Screening of visiting siblings and otherchildren before they are allowed into clinical areas isnecessary to prevent the introduction of childhood ill-nesses and common respiratory infections. Screeningmay be passive, through the use of signs to alert familymembers and visitors with signs and symptoms of com-municable diseases not to enter clinical areas. Moreactive screening may include the completion of ascreening tool or questionnaire to elicit informationrelated to recent exposures or current symptoms. Thisinformation is reviewed by the facility staff, after whichthe visitor is either permitted to visit or is excluded.832
Family and household members visiting pediatricpatients with pertussis and tuberculosis may need tobe screened for a history of exposure, as well as signsand symptoms of current infection. Potentially infec-tious visitors are excluded until they receive appropri-ate medical screening, diagnosis, or treatment. Ifexclusion is not considered to be in the best interestof the patient or family (ie, primary family membersof critically or terminally ill patients), then the sympto-matic visitor must wear a mask while in the health carefacility and remain in the patient’s room, avoiding ex-posure to others, especially in public waiting areasand the cafeteria.
Visitor screening is used consistently on HSCTunits.15,43 However, considering the experience duringthe 2003 SARS outbreaks and the potential for pan-demic influenza, developing effective visitor screeningsystems will be beneficial.9 Education concerning res-piratory hygiene/cough etiquette is a useful adjunct tovisitor screening.
II.N.3.b. Use of Barrier Precautions by Visitors.The use of gowns, gloves, and masks by visitors inhealth care settings has not been addressed specificallyin the scientific literature. Some studies included theuse of gowns and gloves by visitors in the control ofMDROs but did not perform a separate analysis to de-termine whether their use by visitors had a measurable
Siegel et al December 2007 S107
impact.892-894 Family members or visitors who are pro-viding care to or otherwise are in very close contactwith the patient (eg, feeding, holding) may also havecontact with other patients and could contribute totransmission in the absence of effective barrier precau-tions. Specific recommendations may vary by facilityor by unit and should be determined by the specificlevel of interaction.
PART III: PRECAUTIONS TO PREVENTTRANSMISSION OF INFECTIOUS AGENTS
There are 2 tiers of HICPAC/CDC precautions to pre-vent transmission of infectious agents, Standard Pre-cautions and Transmission-Based Precautions.Standard Precautions are intended to be applied tothe care of all patients in all health care settings, re-gardless of the suspected or confirmed presence ofan infectious agent. Implementation of Standard Pre-cautions constitutes the primary strategy for the pre-vention of health care–associated transmission ofinfectious agents among patients and HCWs. Transmis-sion-Based Precautions are for patients who are knownor suspected to be infected or colonized with infectiousagents, including certain epidemiologically importantpathogens, which require additional control measuresto effectively prevent transmission. Because the infect-ing agent often is not known at the time of admission toa health care facility, Transmission-Based Precautionsare used empirically, according to the clinical syn-drome and the likely etiologic agents at the time, andthen modified when the pathogen is identified or atransmissible infectious etiology is ruled out. Examplesof this syndromic approach are presented in Table 2.The HICPAC/CDC Guidelines also include recommen-dations for creating a Protective Environment for allo-geneic HSCT patients.
The specific elements of Standard and Transmis-sion-Based Precautions are discussed in Part II of thisguideline. In Part III, the circumstances in which Stan-dard Precautions, Transmission-Based Precautions,and a Protective Environment are applied are dis-cussed. Tables 4 and 5 summarize the key elementsof these sets of precautions
III.A. Standard Precautions
Standard Precautions combine the major features ofUniversal Precautions779, 895 and Body Substance Isola-tion639 and are based on the principle that all blood,body fluids, secretions, excretions except sweat, nonin-tact skin, and mucous membranes may contain trans-missible infectious agents. Standard Precautionsinclude a group of infection prevention practices thatapply to all patients, regardless of suspected or con-firmed infection status, in any setting in which health
care is delivered (Table 4). These include hand hygiene;use of gloves, gown, mask, eye protection, or faceshield, depending on the anticipated exposure; andsafe injection practices. Also, equipment or items inthe patient environment likely to have been contami-nated with infectious body fluids must be handled in amanner to prevent transmission of infectious agents(eg, wear gloves for direct contact, contain heavilysoiled equipment, properly clean and disinfect or steril-ize reusable equipment before use on another patient).
The application of Standard Precautions during pa-tient care is determined by the nature of the HCW–pa-tient interaction and the extent of anticipated blood,body fluid, or pathogen exposure. For some interac-tions (eg, performing venipuncture), only gloves maybe needed; during other interactions (eg, intubation),use of gloves, gown, and face shield or mask and gog-gles is necessary. Education and training on the princi-ples and rationale for recommended practices arecritical elements of Standard Precautions becausethey facilitate appropriate decision-making and pro-mote adherence when HCWs are faced with new cir-cumstances.654,680-685 An example of the importanceof the use of Standard Precautions is intubation, espe-cially under emergency circumstances when infectiousagents may not be suspected, but later are identified(eg, SARS-CoV, N meningitides). The application of Stan-dard Precautions is described below and summarizedin Table 4. Guidance on donning and removing gloves,gowns and other PPE is presented in Figure 1.
Standard Precautions are also intended to protectpatients by ensuring that HCWs do not carry infectiousagents to patients on their hands or via equipment usedduring patient care.
III.A.1. New Elements of Standard Precautions. In-fection control problems that are identified in thecourse of outbreak investigations often indicate theneed for new recommendations or reinforcement ofexisting infection control recommendations to protectpatients. Because such recommendations are consid-ered a standard of care and may not be included inother guidelines, they are added here to Standard Pre-cautions. Three such areas of practice that have beenadded are respiratory hygiene/cough etiquette, safe in-jection practices, and use of masks for insertion ofcatheters or injection of material into spinal or epiduralspaces through lumbar puncture procedures (eg, mye-logram, spinal or epidural anesthesia). Although mostelements of Standard Precautions evolved from Univer-sal Precautions that were developed for protection ofHCWs, these new elements of Standard Precautionsfocus on protection of patients.
III.A.1.a. Respiratory Hygiene/Cough Etiquette.The transmission of SARS-CoV in emergency depart-ments by patients and their family members during
S108 Vol. 35 No. 10 Supplement 2 Siegel et al
the widespread SARS outbreaks in 2003 highlighted theneed for vigilance and prompt implementation of in-fection control measures at the first point of encounterwithin a health care setting (eg, reception and triageareas in emergency departments, outpatient clinics,and physician offices).21,254,896 The strategy proposedhas been termed respiratory hygiene/cough eti-quette9,827 and is intended to be incorporated into in-fection control practices as a new component ofStandard Precautions. The strategy is targeted at pa-tients and accompanying family members and friendswith undiagnosed transmissible respiratory infections,and applies to any person with signs of illness includ-ing cough, congestion, rhinorrhea, or increased pro-duction of respiratory secretions when entering ahealth care facility.40,41,43 The term cough etiquette isderived from recommended source control measuresfor M tuberculosis.12,126
The elements of respiratory hygiene/cough etiquetteinclude (1) education of health care facility staff, pa-tients, and visitors; (2) posted signs, in language(s) ap-propriate to the population served, with instructionsto patients and accompanying family members orfriends; (3) source control measures (eg, covering themouth/nose with a tissue when coughing and promptdisposal of used tissues, using surgical masks on thecoughing person when tolerated and appropriate); (4)hand hygiene after contact with respiratory secretions;and (5) spatial separation, ideally .3 feet, of personswith respiratory infections in common waiting areaswhen possible. Covering sneezes and coughs and plac-ing masks on coughing patients are proven means ofsource containment that prevent infected personsfrom dispersing respiratory secretions into theair.107,145,897,898 Masking may be difficult in some set-tings, (eg, pediatrics), in which case the emphasis bynecessity may be on cough etiquette.899 Physical prox-imity of , 3 feet has been associated with an increasedrisk for transmission of infections through the dropletroute (eg, N meningitidis103 and group A streptococ-cus114) and thus supports the practice of distancing in-fected persons from others who are not infected. Theeffectiveness of good hygiene practices, especiallyhand hygiene, in preventing transmission of virusesand reducing the incidence of respiratory infectionsboth within and outside900-902 health care settings issummarized in several reviews.558,716,903
These measures should be effective in decreasing therisk of transmission of pathogens contained in largerespiratory droplets (eg, influenza virus,23 adenovi-rus,111 B pertussis,826 and M pneumoniae112). Althoughfever will be present in many respiratory infections,patients with pertussis and mild upper respiratory tractinfections are often afebrile. Therefore, the absence offever does not always exclude a respiratory infection.
Patients who have asthma, allergic rhinitis, or chronicobstructive lung disease also may be coughing andsneezing. Although these patients often are not infec-tious, cough etiquette measures are prudent.
HCWs are advised to observe Droplet Precautions (ie,wear a mask) and hand hygiene when examining andcaring for patients with signs and symptoms of a respi-ratory infection. HCWs who have a respiratory infectionare advised to avoid direct patient contact, especiallywith high-risk patients. If this is not possible, then amask should be worn while providing patient care.
III.A.1.b. Safe Injection Practices. The investiga-tion of 4 large outbreaks of HBV and HCV among pa-tients in ambulatory care facilities in the UnitedStates identified a need to define and reinforce safe in-jection practices.452 The 4 outbreaks occurred in a pri-vate medical practice, a pain clinic, an endoscopyclinic, and a hematology/oncology clinic. The primarybreaches in infection control practice that contributedto these outbreaks were reinsertion of used needlesinto a multiple-dose vial or solution container (eg, sa-line bag) and use of a single needle/syringe to adminis-ter intravenous medication to multiple patients. In 1 ofthese outbreaks, preparation of medications in thesame workspace where used needle/syringes were dis-mantled also may have been a contributing factor.These and other outbreaks of viral hepatitis couldhave been prevented by adherence to basic principlesof aseptic technique for the preparation and adminis-tration of parenteral medications.452,453 These includethe use of a sterile, single-use, disposable needle andsyringe for each injection given and prevention of con-tamination of injection equipment and medication.Whenever possible, use of single-dose vials is preferredover multiple-dose vials, especially when medicationswill be administered to multiple patients.
Outbreaks related to unsafe injection practices indi-cate that some HCWs are unaware of, do not under-stand, or do not adhere to basic principles ofinfection control and aseptic technique. A survey ofUS health care workers who provide medicationthrough injection found that 1% to 3% reused thesame needle and/or syringe on multiple patients.904
Among the deficiencies identified in recent outbreakswere a lack of oversight of personnel and failure to fol-low up on reported breaches in infection control prac-tices in ambulatory settings. Therefore, to ensure thatall HCWs understand and adhere to recommendedpractices, principles of infection control and aseptictechnique need to be reinforced in training programsand incorporated into institutional polices that aremonitored for adherence.453
III.A.1.c. Infection Control Practices for SpecialLumbar Puncture Procedures. In 2004, the CDC inves-tigated 8 cases of postmyelography meningitis that
Siegel et al December 2007 S109
either were reported to the CDC or identified through asurvey of the Emerging Infections Network of the Infec-tious Disease Society of America. Blood and/or cerebro-spinal fluid of all 8 cases yielded streptococcal speciesconsistent with oropharyngeal flora and there werechanges in the CSF indices and clinical status indicativeof bacterial meningitis. Equipment and products usedduring these procedures (eg, contrast media) were ex-cluded as probable sources of contamination. Proce-dural details available for 7 cases determined thatantiseptic skin preparations and sterile gloves hadbeen used. However, none of the clinicians wore aface mask, giving rise to the speculation that droplettransmission of oralpharyngeal flora was the mostlikely explanation for these infections. Bacterial men-ingitis after myelography and other spinal procedures(eg, lumbar puncture, spinal and epidural anesthesia,intrathecal chemotherapy) has been reported previ-ously.905-914 As a result, the question of whether facemasks should be worn to prevent droplet spread oforal flora during spinal procedures (eg, myelography,lumbar puncture, spinal anesthesia) has beendebated.915, 916 Face masks are effective in limitingthe dispersal of oropharyngeal droplets917 and are rec-ommended for the placement of central venous cathe-ters.918 In October 2005, HICPAC reviewed the evidenceand concluded that there is sufficient experience towarrant the additional protection of a face mask forthe individual placing a catheter or injecting materialinto the spinal or epidural space.
III.B. Transmission-Based Precautions
There are 3 categories of Transmission-Based Pre-cautions: Contact Precautions, Droplet Precautions,and Airborne Precautions. Transmission-Based Precau-tions are used when the route(s) of transmission is (are)not completely interrupted using Standard Precautionsalone. For some diseases that have multiple routes oftransmission (eg, SARS), more than 1 Transmission-Based Precautions category may be used. When usedeither singly or in combination, they are always usedin addition to Standard Precautions. See Appendix Afor recommended precautions for specific infections.When Transmission-Based Precautions are indicated,efforts must be made to counteract possible adverse ef-fects on patients (ie, anxiety, depression and othermood disturbances,919-921 perceptions of stigma,922 re-duced contact with clinical staff,923-925 and increases inpreventable adverse events564) to improve acceptanceby the patients and adherence by HCWs.
III.B.1. Contact Precautions. Contact Precautionsare intended to prevent transmission of infectiousagents, including epidemiologically important micro-organisms, which are spread by direct or indirect
contact with the patient or the patient’s environmentas described in Section I.B.3.a. The specific agentsand circumstance for which Contact Precautions areindicated are found in Appendix A. The application ofContact Precautions for patients infected or colonizedwith MDROs is described in the 2006 HICPAC/CDCMDRO guideline.926 Contact Precautions also applywhere the presence of excessive wound drainage, fecalincontinence, or other discharges from the bodysuggest an increased potential for extensive environ-mental contamination and risk of transmission. A sin-gle-patient room is preferred for patients who requireContact Precautions. When a single-patient room isnot available, consultation with infection control per-sonnel is recommended to assess the various risksassociated with other patient placement options (eg,cohorting, keeping the patient with an existing room-mate). In multipatient rooms, $ 3 feet spatial separa-tion between beds is advised to reduce theopportunities for inadvertent sharing of items betweenthe infected/colonized patient and other patients. HCWscaring for patients on Contact Precautions wear a gownand gloves for all interactions that may involve contactwith the patient or potentially contaminated areas inthe patient’s environment. Donning PPE on room entryand discarding before exiting the patient room is done tocontain pathogens, especially those that have been im-plicated in transmission through environmental con-tamination (eg, VRE, C difficile, noroviruses and otherintestinal tract pathogens, RSV).54,72,73,78,273,274,739
III.B.2. Droplet Precautions. Droplet Precautions areintended to prevent transmission of pathogens spreadthrough close respiratory or mucous membrane con-tact with respiratory secretions as described in SectionI.B.3.b. Because these pathogens do not remain infec-tious over long distances in a health care facility, spe-cial air handling and ventilation are not required toprevent droplet transmission. Infectious agents forwhich Droplet Precautions are indicated are listed inAppendix A and include B pertussis, influenza virus, ad-enovirus, rhinovirus, N meningitides, and group Astreptococcus (for the first 24 hours of antimicrobialtherapy). A single-patient room is preferred for patientswho require Droplet Precautions. When a single-pa-tient room is not available, consultation with infectioncontrol personnel is recommended to assess the vari-ous risks associated with other patient placement op-tions (eg, cohorting, keeping the patient with anexisting roommate). Spatial separation of $ 3 feetand drawing the curtain between patient beds is espe-cially important for patients in multibed rooms with in-fections transmitted by the droplet route. HCWs wear amask (a respirator is not necessary) for close contactwith infectious patient; the mask is generally donnedon room entry. Patients on Droplet Precautions who
S110 Vol. 35 No. 10 Supplement 2 Siegel et al
must be transported outside of the room should wear amask if tolerated and follow respiratory hygiene/coughetiquette.
III.B.3. Airborne Precautions. Airborne Precautionsprevent transmission of infectious agents that remaininfectious over long distances when suspended in theair (eg, rubeola virus [measles], varicella virus [chick-enpox], M tuberculosis, and possibly SARS-CoV), asdescribed in Section I.B.3.c and Appendix A. The pre-ferred placement for patients who require AirbornePrecautions is in an AIIR, a single-patient room equip-ped with special air handling and ventilation capacitythat meet the AIA/Facility Guidelines Institute stan-dards for AIIRs (ie, monitored negative pressure relativeto the surrounding area; 12 air exchanges per hour fornew construction and renovation and 6 air exchangesper hour for existing facilities; air exhausted directlyto the outside or recirculated through HEPA filtrationbefore return).12,13 Some states require the availabilityof such rooms in hospitals, emergency departments,and nursing homes that care for patients with M tuber-culosis. A respiratory protection program that includeseducation about use of respirators, fit testing, and userseal checks is required in any facility with AIIRs. In set-tings where Airborne Precautions cannot be imple-mented due to limited engineering resources (eg,physician offices), masking the patient, placing the pa-tient in a private room (eg, office examination room)with the door closed, and providing N95 or higher-levelrespirators or masks if respirators are not available forHCWs will reduce the likelihood of airborne transmis-sion until the patient is either transferred to a facilitywith an AIIR or returned to the home environment,as deemed medically appropriate. HCWs caring forpatients on Airborne Precautions wear a mask or respi-rator, depending on the disease-specific recommenda-tions (see Section II.E.4, Table 2, and Appendix A), thatis donned before room entry. Whenever possible, non-immune HCWs should not care for patients withvaccine-preventable airborne diseases (eg, measles,chickenpox, smallpox).
III.C. Syndromic and Empiric Applications ofTransmission-Based Precautions
Diagnosis of many infections requires laboratoryconfirmation. Because laboratory tests, especiallythose that depend on culture techniques, often require2 or more days for completion, Transmission-BasedPrecautions must be implemented while test resultsare pending, based on the clinical presentation andlikely pathogens. Use of appropriate Transmission-Based Precautions at the time a patient develops symp-toms or signs of transmissible infection, or arrives at ahealth care facility for care, reduces transmission
opportunities. Although it is not possible to identifyprospectively all patients needing Transmission-BasedPrecautions, certain clinical syndromes and conditionscarry a sufficiently high risk to warrant their use empir-ically while confirmatory tests are pending (see Table2). ICPs are encouraged to modify or adapt this table ac-cording to local conditions.
III.D. Discontinuation of Transmission-BasedPrecautions
Transmission-Based Precautions remain in effect forlimited periods (ie, while the risk for transmission ofthe infectious agent persists or for the duration of theillness (see Appendix A). For most infectious diseases,this duration reflects known patterns of persistenceand shedding of infectious agents associated with thenatural history of the infectious process and its treat-ment. For some diseases (eg, pharyngeal or cutaneousdiphtheria, RSV), Transmission-Based Precautions re-main in effect until culture or antigen-detection test re-sults document eradication of the pathogen and, forRSV, symptomatic disease is resolved. For other dis-eases (eg, M tuberculosis), state laws and regulationsand health care facility policies may dictate the dura-tion of precautions.12 In immunocompromised pa-tients, viral shedding can persist for prolongedperiods of time (many weeks to months) and transmis-sion to others may occur during that time; therefore,the duration of contact and/or droplet precautionsmay be prolonged for many weeks.499,927-932
The duration of Contact Precautions for patientswho are colonized or infected with MDROs remainsundefined. MRSA is the only MDRO for which effectivedecolonization regimens are available.866 However,carriers of MRSA who have negative nasal cultures aftera course of systemic or topical therapy may resumeshedding MRSA in the weeks after therapy.933,934 Al-though early guidelines for VRE suggested discontinu-ation of Contact Precautions after 3 stool culturesobtained at weekly intervals proved negative,739 subse-quent experiences have indicated that such screeningmay fail to detect colonization that can persist for .
1 year.27,935-937 Likewise, available data indicate thatcolonization with VRE, MRSA,938 and possibly MDR-GNB can persist for many months, especially in thepresence of severe underlying disease, invasive de-vices, and recurrent courses of antimicrobial agents.
It may be prudent to assume that MDRO carriers arecolonized permanently and manage them accordingly.Alternatively, an interval free of hospitalizations, anti-microbial therapy, and invasive devices (eg, 6 or 12months) before reculturing patients to document clear-ance of carriage may be used. Determination of the beststrategy awaits the results of additional studies. See the
Siegel et al December 2007 S111
2006 HICPAC/CDC MDRO guideline926 for a discussionof possible criteria to discontinue Contact Precautionsfor patients colonized or infected with MDROs.
III.E. Application of Transmission-BasedPrecautions in Ambulatory and Home CareSettings
Although Transmission-Based Precautions generallyapply in all health care settings, exceptions exist. Forexample, in home care, AIIRs are not available. Further-more, family members already exposed to diseasessuch as varicella and tuberculosis would not use masksor respiratory protection, but visiting HCWs wouldneed to use such protection. Similarly, managementof patients colonized or infected with MDROs may ne-cessitate Contact Precautions in acute care hospitalsand in some LTCFs when there is continued transmis-sion, but the risk of transmission in ambulatory careand home care has not been defined. Consistent useof Standard Precautions may suffice in these settings,but more information is needed.
III.F. Protective Environment
A PE is designed for allogeneic HSCT patients to min-imize fungal spore counts in the air and reduce the riskof invasive environmental fungal infections (see Table5 for specifications).11,13-15 The need for such controlshas been demonstrated in studies of aspergillosis out-breaks associated with construction.11,14,15,157,158 Asdefined by the AIA13 and presented in detail in theCDC’s 2003 Guideline for Environmental Infection Con-trol in Health Care Facilities,11,860 air quality for HSCTpatients is improved through a combination of environ-mental controls that include (1) HEPA filtration of in-coming air, (2) directed room air flow, (3) positiveroom air pressure relative to the corridor, (4) well-sealedrooms (including sealed walls, floors, ceilings, windows,electrical outlets) to prevent flow of air from the outside,(5) ventilation to provide $ 12 air changes per hour, (6)strategies to minimize dust (eg, scrubbable surfacesrather than upholstery939 and carpet,940 and routinelycleaning crevices and sprinkler heads), and (7) prohibit-ing dried and fresh flowers and potted plants in therooms of HSCT patients. The latter is based on molecu-lar typing studies that have found indistinguishablestrains of Aspergillus terreus in patients with hemato-logic malignancies and in potted plants in the vicinityof the patients.941-943 The desired quality of air may beachieved without incurring the inconvenience or ex-pense of laminar airflow.15,157 To prevent inhalation offungal spores during periods when construction, renova-tion, or other dust-generating activities that may be on-going in and around the health care facility, it has beenrecommended that severely immunocompromised
patients wear a high-efficiency respiratory protectiondevice (eg, an N95 respirator) when they leave thePE.11,14,944 The use of masks or respirators by HSCT pa-tients when they are outside of the PE for prevention ofenvironmental fungal infections in the absence of con-struction has not been evaluated. A PE does not includethe use of barrier precautions beyond those indicatedfor Standard Precuations and Transmission-Based Pre-cautions. No published reports support the benefit ofplacing patients undergoing solid organ transplantationor other immunocompromised patients in a PE.
PART IV: RECOMMENDATIONS
These recommendations are designed to preventtransmission of infectious agents among patients andHCWs in all settings where health care is delivered.As in other CDC/HICPAC guidelines, each recommenda-tion is categorized on the basis of existing scientificdata, theoretical rationale, applicability, and, whenpossible, economic impact. The CDC/HICPAC systemfor categorizing recommendations is as follows:
Category IA. Strongly recommended for implemen-tation and strongly supported by well-designed exper-imental, clinical, or epidemiologic studies.
Category IB. Strongly recommended for implemen-tation and supported by some experimental, clinical, orepidemiologic studies and a strong theoreticalrationale.
Category IC. Required for implementation, as man-dated by federal and/or state regulation or standard.
Category II. Suggested for implementation and sup-ported by suggestive clinical or epidemiologic studiesor a theoretical rationale.
No recommendation; unresolved issue. Practices forwhich insufficient evidence or no consensus regardingefficacy exists.
I. Administrative Responsibilities
Health care organization administrators should en-sure the implementation of recommendations speci-fied in this section.
I.A. Incorporate preventing transmission of infectiousagents into the objectives of the organization’s pa-tient and occupational safety programs.542-545,560,
629,625,945 Category IB/ICI.B. Make preventing transmission of infectious agents
a priority for the health care organization. Provideadministrative support, including fiscal and hu-man resources for maintaining infection controlprograms.433,547,548,551,558,560-563,565,661,945 Cate-gory IB/ICI.B.1. Ensure that individuals with training in in-
fection control are employed by or are
S112 Vol. 35 No. 10 Supplement 2 Siegel et al
available by contract to all health care facili-ties, so that the infection control programis managed by 1 or more qualified indi-viduals.315,551,565,572,575,574,945,946 CategoryIB/ICI.B.1.a. Determine thespecific infectioncontrol
full-time equivalents according to thescope of the infection control program,the complexity of the health care facil-ity or system, the characteristics of thepatient population, the unique or ur-gent needs of the facility and commu-nity, and proposed staffing levelsbasedonsurveyresultsandrecommen-dations from professional organiza-tions.315,433,548,551,565,568,572,574,947,948
Category IBI.B.2. Include prevention of HAIs as a deter-
minant of bedside nurse staffing levelsand composition, especially in high-riskunits.417,550,582,584-589,591-596 Category IB
I.B.3. Delegate authority to infection control per-sonnel or their designees (eg, patient careunit charge nurses) for making infectioncontrol decisions concerning patient place-ment and assignment of Transmission-BasedPrecautions.433,548,856,945 Category IC
I.B.4. Involve infection control personnel in deci-sions on facility construction and design, de-termination of AIIR and PE capacity needs,and environmental assessments.11-13, 949,950
Category IB/ICI.B.4.a. Provide ventilation systems required
for a sufficient number of AIIRs (asdetermined by a risk assessment)and PEs in health care facilities thatprovide care to patients for whomsuch rooms are indicated, accordingto published recommendations.11-
13,15 Category IB/ICI.B.5. Involve infection control personnel in the se-
lection and postimplementation evaluationof medical equipment and supplies andchanges in practice that could affect therisk of HAI.951,952 Category IC
I.B.6. Ensure availability of human and fiscal re-sources to provide clinical microbiology labo-ratory support, including a sufficient numberof medical technologists trained in microbiol-ogy, appropriate to the health care setting, formonitoring transmission of microorganisms,planning and conducting epidemiologic in-vestigations, and detecting emerging patho-gens. Identify resources for performingsurveillance cultures, rapid diagnostic testing
for viral and other selected pathogens, prepa-ration of antimicrobial susceptibility sum-mary reports, trend analysis, and moleculartyping of clustered isolates (performed eitheronsite or in a reference laboratory) and usethese resources according to facility-specificepidemiologic needs, in consultation withclinical microbiologists.552,553,597,598,602,604-
606,608,609,611,613-616,953 Category IBI.B.7. Provide human and fiscal resources to meet
occupational health needs related to infec-tion control (eg, HCWs immunization, post-exposure evaluation and care, evaluationand management of HCWs with communi-cable infections.12,17,134,689,738,878-880 Cate-gory IB/IC
I.B.8. In all areas where health care is delivered,provide supplies and equipment necessaryfor the consistent observance of StandardPrecautions, including hand hygiene pro-ducts and PPE (eg, gloves, gowns, face andeye protection).558,738,945 Category IB/IC
I.B.9. Develop and implement policies and proce-dures to ensure that reusable patient careequipment is cleaned and reprocessed ap-propriately before use on another pa-tient.11,87,836,954-959 Category IA/IC
I.C. Develop and implement processes to ensure over-sight of infection control activities appropriate tothe health care setting and assign responsibilityfor oversight of infection control activities to an in-dividual or group within the health care organiza-tion that is knowledgeable about infectioncontrol.433,548,565 Category II
I.D. Develop and implement systems for early detec-tion and management (eg, use of appropriate in-fection control measures, including isolationprecautions, PPE) of potentially infectious personsat initial points of patient encounter in outpatientsettings (eg, triage areas, emergency departments,outpatient clinics, physician offices) and at thetime of admission to hospitals andLTCFs.9,122,134,253,826 Category IB
I.E. Develop and implement policies and procedures tolimit patient visitation by persons with signs orsymptoms of a communicable infection. Screenvisitors to high-risk patient care areas (eg, oncologyunits, HSCT units, intensive care units, other se-verely immunocompromised patients) for possibleinfection.24,41,43,960,961Category IB
I.F. Identify performance indicators of the effective-ness of organization-specific measures to preventtransmission of infectious agents (Standard Precau-tions and Transmission-Based Precautions), estab-lish processes to monitor adherence to those
Siegel et al December 2007 S113
performance measures, and provide feedback tostaff members.554,665-667,703,704,739,962 Category IB
II. Education and Training
II.A. Provide job- or task-specific education and train-ing on preventing transmission of infectiousagents associated with health care during orienta-tion to the health care facility; update informationperiodically during ongoing education programs.Target all HCWs for education and training, in-cluding but not limited to medical, nursing, clini-cal technicians, and laboratory staff; propertyservice (housekeeping), laundry, maintenanceand dietary workers; students; contract staff; andvolunteers. Document competency initially andrepeatedly, as appropriate, for the specific staffpositions. Develop a system to ensure that HCWsemployed by outside agencies meet these educa-tion and training requirements through programsoffered by the agencies or by participation in thehealth care facility’s program designed for full-time personnel.126,558,560,561,654,680-683,685,687,688,
701,892,918,963 Category IBII.A.1. Include in education and training programs,
information concerning use of vaccines asan adjunctive infection control mea-sure.17,610,689,873 Category IB
II.A.2. Enhance education and training by apply-ing principles of adult learning, using read-ing level and language appropriate materialfor the target audience, and using online ed-ucational tools available to the institu-tion.657,693,694,696,697,699,964 Category IB
II.B. Provide instructional materials for patients andvisitors on recommended hand hygiene andrespiratory hygiene/cough etiquette practicesand the application of Transmission-Based Pre-cautions.9,708,709,961 Category II
III. Surveillance
III.A. Monitor the incidence of epidemiologically im-portant organisms and targeted HAIs that have asubstantial impact on outcome and for which ef-fective preventive interventions are available. Useinformation collected through surveillance ofhigh-risk populations, procedures, devices, andhighly transmissible infectious agents to detecttransmission of infectious agents in the healthcare facility.565,670,671,672,674,686,918,965-968 Cate-gory IA
III.B. Apply the following epidemiologic principles ofinfection surveillance:662,663,670,672,965,967 Cate-gory IB
d Use standardized definitions of infection.d Use laboratory-based data (when available).d Collect epidemiologically important variables
(eg, patient locations and/or clinical service inhospitals and other large multiunit facilities,population-specific risk factors [eg, low birthweight neonates], underlying conditions thatpredispose to serious adverse outcomes).
d Analyze data to identify trends that may indi-cated increased rates of transmission.
d Feedback information on trends in the incidenceand prevalence of HAIs, probable risk factors,and prevention strategies and their impact tothe appropriate health care providers, organiza-tion administrators, and as required by localand state health authorities.
III.C. Develop and implement strategies to reduce risksfor transmission and evaluate effective-ness565,672, 683,961,968,969 Category IB
III.D. When transmission of epidemiologically impor-tant organisms continues despite implementa-tion and documented adherence to infectionprevention and control strategies, obtain consul-tation from persons knowledgeable in infectioncontrol and health care epidemiology to reviewthe situation and recommend additional mea-sures for control.247,566,686 Category IB
III.E. Periodically review information on community orregional trends regarding the incidence and prev-alence of epidemiologically important organisms(eg, influenza, RSV, pertussis, invasive group Astreptococcal disease, MRSA, VRE) (including inother health care facilities) that may affect trans-mission of organisms within the facil-ity.397,686,970-972 Category II
IV. Standard Precautions
Assume that every person is potentially infected orcolonized with an organism that could be transmittedin the health care setting and apply the following infec-tion control practices during the delivery of health care.
IV.A. Hand HygieneIV.A.1. During the delivery of health care, avoid un-
necessary touching of surfaces in closeproximity to the patient to prevent both con-tamination ofclean hands from environmen-tal surfaces and transmission of pathogensfrom contaminated hands to surfaces.72,73,
738,799,973 {CDC, 2001 #970. Category IB/ICIV.A.2. When hands are visibly dirty, contaminated
with proteinaceous material, or visiblysoiled with blood or body fluids, washhands with either a nonantimicrobial soap
S114 Vol. 35 No. 10 Supplement 2 Siegel et al
and water or an antimicrobial soap andwater.558 Category IA
IV.A.3. If hands are not visibly soiled, or after re-moving visible material with nonantimicro-bial soap and water, decontaminate handsin the clinical situations described inIV.A.2.a–f. The preferred method of handdecontamination is with an alcohol-basedhand rub.561,974 Alternatively, hands maybe washed with an antimicrobial soap andwater. Frequent use of an alcohol-basedhand rub immediately after handwashingwith nonantimicrobial soap may increasethe frequency of dermatitis.558 Category IB
Perform hand hygiene:IV.A.3.a. Before having direct contact with
patients.663,975 Category IBIV.A.3.b. After contact with blood, body
fluids or excretions, mucous mem-branes, nonintact skin, or wounddressings.663 Category IA
IV.A.3.c. After contact with a patient’s intactskin (eg, when measuring pulseor blood pressure or lifting apatient).167,976-978 Category IB
IV.A.3.d. If hands will be moving from a con-taminated body site to a clean bodysite during patient care. Category II
IV.A.3.e. After contact with inanimate ob-jects (including medical equipment)in the immediate vicinity of the pa-tient.72,73,88,799,979,980 Category II
IV.A.3.f. After removing gloves.727,740,741
Category IBIV.A.4. Wash hands with nonantimicrobial soap
and water or with antimicrobial soap andwater if contact with spores (eg, C difficileor B anthracis) is likely to have occurred.The physical action of washing and rinsinghands under such circumstances is recom-mended because alcohols, chlorhexidine,iodophors, and other antiseptic agentshave poor activity against spores.558,954,981
Category IIIV.A.5. Do not wear artificial fingernails or ex-
tenders if duties include direct contactwith patients at high risk for infection andassociated adverse outcomes (eg, those inICUs or operating rooms).30,31,558,721-723
Category IAIV.A.5.a. Develop an organizational policy
on the wearing of nonnatural nailsby HCWs who have direct contactwith patients outside of the groupsspecified above.982 Category II
IV.B. Personal protective equipment (see Fig 1)IV.B.1. Observe the following principles of use:
IV.B.1.a. Wear PPE, as described in IV.B.2–4, when the nature of the antici-pated patient interaction indicatesthat contact with blood or bodyfluids may occur.738,779,895 Cate-gory IB/IC
IV.B.1.b. Prevent contamination of clothingand skin during the process of re-moving PPE (see Fig 1). Category II
IV.B.1.c. Before leaving the patient’s room orcubicle, remove and discardPPE.18,738 Category IB/IC
IV.B.2. GlovesIV.B.2.a. Wear gloves when it can be reason-
ably anticipated that contact withblood or other potentially infectiousmaterials, mucous membranes,nonintact skin, or potentially con-taminated intact skin (eg, of a pa-tient incontinent of stool or urine)could occur.18,727,738,740,779,983 Cate-gory IB/IC
IV.B.2.b. Wear gloves with fit and durabilityappropriate to the task.558,730,731,
738,984,985 Category IBIV.B.2.b.i. Wear disposable medical ex-
amination gloves for providingdirect patient care.
IV.B.2.b.ii. Wear disposable medical ex-amination gloves or reusableutility gloves for cleaningthe environment or medicalequipment.
IV.B.2.c. Remove gloves after contact with apatient and/or the surroundingenvironment (including medicalequipment) using proper techniqueto prevent hand contamination (seeFig 1). Do not wear the same pair ofgloves for the care of more than1 patient. Do not wash gloves forthe purpose of reuse, because thispractice has been associated withtransmission of pathogens.558,727,
740-742,986 Category IBIV.B.2.d. Change gloves during patient care if
the hands will move from a con-taminated body site (eg, perinealarea) to a clean body site (eg,face). Category II
IV.B.3. GownsIV.B.3.a. Wear a gown appropriate to the task
to protect skin and prevent soiling
Siegel et al December 2007 S115
or contamination of clothing duringprocedures and patient care activi-ties when contact with blood,body fluids, secretions, or excre-tions is anticipated.738,779,894 Cate-gory IB/IC
IV.B.3.a.i. Wear a gown for direct patientcontact if the patient has un-contained secretions or excre-tions.24,88,89,738,743 CategoryIB/IC
IV.B.3.a.ii. Remove gown and performhand hygiene before leavingthe patient’s environment.24,
88,89,738,743 Category IB/ICIV.B.3.b. Do not reuse gowns, even for re-
peated contacts with the same pa-tient. Category II
IV.B.3.c. Routine donning of gowns on en-trance into a high-risk unit (eg,ICU, NICU, HSCT unit) is not indi-cated.364,746-749 Category IB
IV.B.4. Mouth, nose, and eye protectionIV.B.4.a. Use PPE to protect the mucous
membranes of the eyes, nose, andmouth during procedures and pa-tient care activities that are likelyto generate splashes or sprays ofblood, body fluids, secretions, andexcretions. Select masks, goggles,face shields, and combinationsof these according to the needanticipated by the task to beperformed.113,738,779,895 CategoryIB/IC
IV.B.5. During aerosol-generating procedures (eg,bronchoscopy, suctioning of the respiratorytract [if not using in-line suction catheters],endotracheal intubation) in patients whoare not suspected of being infected withan agent for which respiratory protectionis otherwise recommended (eg, M tubercu-losis, SARS, or hemorrhagic fever viruses),wear one of the following: a face shieldthat fully covers the front and sides of theface, a mask with attached shield, or amask and goggles (in addition to glovesand gown).93-96,113,126,134 Category IB
IV.C. Respiratory hygiene/cough etiquetteIV.C.1. Educate HCWs on the importance of source
control measures to contain respiratory se-cretions, to prevent droplet and fomitetransmission of respiratory pathogens, es-pecially during seasonal outbreaks of viralrespiratory tract infections (eg, influenza,
IV.C.2. Implement the following measures to con-tain respiratory secretions in patients andaccompanying individuals who have signsand symptoms of a respiratory infection,beginning at the point of initial encounterin a health care setting (eg, triage, receptionand waiting areas in emergency depart-ments, outpatient clinics, and physicians’offices).20,24,145,901,987
IV.C.2.a. Post signs at entrances and in stra-tegic places (eg, elevators, cafete-rias) within ambulatory andinpatient settings with instructionsto patients and other persons withsymptoms of respiratory infectionto cover their mouths and noseswhen coughing or sneezing, useand dispose of tissues, and performhand hygiene after hands havebeen in contact with respiratory se-cretions. Category II
IV.C.2.b. Provide tissues and no-touch recep-tacles (eg, foot pedal–operated lidor open, plastic-lined wastebasket)for disposal of tissues.20 Category II
IV.C.2.c. Provide resources and instructionsfor performing hand hygiene in ornear waiting areas in ambulatoryand inpatient settings; provide con-veniently located dispensers of al-cohol-based hand rubs and, wheresinks are available, supplies forhandwashing.558,901 Category IB
IV.C.2.d. During periods of increased preva-lence of respiratory infections inthe community (as indicated by,eg, increased school absenteeism,increased number of patients seek-ing care for respiratory infection),offer masks to coughing patientsand other symptomatic persons(eg, persons who accompany ill pa-tients) on entry into the facility ormedical office126,898,899 and en-courage them to maintain specialseparation (ideally, at least 3 feet)from others in common waitingareas.20,23,103,111,114,134 Category IB
IV.C.2.d.i. Some facilities may find it lo-gistically easier to institutethis recommendation year-round as a standard of prac-tice. Category II
S116 Vol. 35 No. 10 Supplement 2 Siegel et al
IV.D. Patient placementIV.D.1. Include the potential for transmission of in-
fectious agents in patient placement deci-sions. Place patients who pose a risk fortransmission to others (eg, those with uncon-tained secretions, excretions, or wounddrainage; infants with suspectedviral respira-tory or gastrointestinal infections) in asingle-patient room when available.24,409,429,
434,792,795,796,805,988 Category IBIV.D.2. Determine patient placement based on the
following factors:d Route(s) of transmission of the known or
suspected infectious agentd Risk factors for transmission in the in-
fected patientd Risk factors for adverse outcomes resulting
from an HAI in other patients in the area orroom being considered for patientplacement
d Availability of single-patient roomsd Patient options for room sharing (eg, co-
horting patients with the same infection)Category II
IV.E. Patient care equipment and instruments/devices954
IV.E.1. Establish policies and procedures for con-taining, transporting, and handling patientcare equipment and instruments/devicesthat may be contaminated with blood orbody fluids18,738,973 Category IB/IC
IV.E.2. Remove organic material from critical andsemicritical instrument/devices, using rec-ommended cleaning agents before high-level disinfection and sterilization to enableeffective disinfection and sterilization pro-cesses.835,989,990 Category IA
IV.E.3. Wear PPE (eg, gloves, gown), according tothe level of anticipated contamination,when handling patient care equipmentand instruments/devices that is visiblysoiled or may have been in contact withblood or body fluids.18,738,973 Category IB/IC
IV.F. Care of the environment11
IV.F.1. Establish policies and procedures for rou-tine and targeted cleaning of environmentalsurfaces as indicated by the level of patientcontact and degree of soiling.11 Category II
IV.F.2. Clean and disinfect surfaces likely to becontaminated with pathogens, includingthose in close proximity to the patient (eg,bed rails, over bed tables) and frequentlytouched surfaces in the patient care envi-ronment (eg, door knobs, surfaces in andsurrounding toilets in patient rooms) on a
more frequent schedule compared withthat for other surfaces (eg, horizontal sur-faces in waiting rooms).11,72,73,739,745,
799,833,991-993 Category IBIV.F.3. Use EPA-registered disinfectants that have
microbiocidal (ie, killing) activity againstthe pathogens most likely to contaminatethe patient care environment. Use in accor-dance with manufacturer’s instructions.841-
843,954,994 Category IB/ICIV.F.3.a. Review the efficacy of disinfectants
in use when evidence of continuingtransmission of an infectious agent(eg, rotavirus, C difficile, norovirus)may indicate resistance to theproduct and a change to a moreeffective disinfectant as indi-cated.274,841,846 Category II
IV.F.4. In facilities that provide health care to pedi-atric patients or that have waiting areas withchildren’s toys (eg, obstetric/gynecology of-fices and clinics), establish policies and pro-cedures for cleaning and disinfecting toys atregular intervals.80,378 Category IB
Consider the following principles when developingthis policy and procedures: Category II
d Select play toys that can be easily cleanedand disinfected.
d Do not permit use of stuffed furry toys ifthey will be shared.
d Clean and disinfect large stationary toys(eg, climbing equipment) at least weeklyand whenever visibly soiled.
d If toys are likely to be mouthed, rinse withwater after disinfection; alternatively,wash in a dishwasher.
d When a toy requires cleaning and disinfec-tion, do so immediately or store in a desig-nated labeled container separate from toysthat are clean and ready for use.
IV.F.5. Include multiuse electronic equipment inpolicies and procedures for preventingcontamination and for cleaning and disin-fection, especially those items that areused by patients, those used during deliv-ery of patient care, and mobile devicesthat are moved in and out of patient roomsfrequently (eg, daily).849,850,851,995 CategoryIB
IV.F.5.a. No recommendation for use of re-movable protective covers or wash-able keyboards. Unresolved issue
IV.G. Textiles and laundryIV.G.1. Handle used textiles and fabrics with mini-
mum agitation to avoid contamination of
Siegel et al December 2007 S117
air, surfaces, and persons.738,996,997 Cate-gory IB/IC
IV.G.2. If laundry chutes are used, ensure that theyare properly designed, maintained, andused in a manner to minimize dispersionof aerosols from contaminated laun-dry.11,13,998,999 Category IB/IC
IV.H. Safe injection practicesThe following recommendations apply to the use ofneedles, cannulas that replace needles, and, where ap-plicable, intravenous delivery systems:453
IV.H.1. Use aseptic technique to avoid contamina-tion of sterile injection equipment1000,1001
Category IAIV.H.2. Do not administer medications from a sy-
ringe to multiple patients, even if the nee-dle or cannula on the syringe is changed.Needles, cannulae, and syringes are sterile,single-use items; they should not be reusedfor another patient or to access a medica-tion or solution that might be used for asubsequent patient.452,918,1002,1003 Cate-gory IA
IV.H.3. Use fluid infusion and administration sets(ie, intravenous bags, tubing and connec-tors) for one patient only and dispose ofappropriately after use. Consider a syringeor needle/cannula to be contaminatedonce it has been used to enter or connectto a patient’s intravenous infusion bag oradministration set.452 Category IB
IV.H.4. Use single-dose vials for parenteral medica-tions whenever possible.452 Category IA
IV.H.5. Do not administer medications from single-dose vials or ampules to multiple patientsor combine leftover contents for lateruse.368,452,1003 Category IA
IV.H.6. If multidose vials must be used, both theneedle or cannula and syringe used to ac-cess the multidose vial must be ster-ile.452,1000 Category IA
IV.H.7. Do not keep multidose vials in the immediatepatient treatment area. Store in accordancewith the manufacturer’s recommendations;discard if sterility is compromised or ques-tionable.452,1001 Category IA
IV.H.8. Do not use bags or bottles of intravenoussolution as a common source of supplyfor multiple patients.452,1004 Category IB
IV.I. Infection control practices for special lumbarpuncture procedures
Wear a surgical mask when placing a catheter or inject-ing material into the spinal canal or subdural space (ie,during myelograms, lumbar puncture and spinal or ep-idural anesthesia).904-912,916,1005 Category IB
IV.J. Worker safetyAdhere to federal and state requirements for protectionof HCWs from exposure to bloodborne pathogens.738
Category IC
V. Transmission-Based Precautions
V.A. General principlesV.A.1. In addition to Standard Precautions, use
Transmission-Based Precautions forpatients with documented or suspected in-fection or colonization with highly trans-missible or epidemiologically importantpathogens for which additional precautionsare needed to prevent transmission (seeAppendix A).24,93,126,141,305,805,1006 CategoryIA
V.A.2. Extend the duration of Transmission-BasedPrecautions, (eg, Droplet, Contact) for im-munosuppressed patients with viral infec-tions due to prolonged shedding of viralagents that may be transmitted toothers.927,930-932,1007-1009 Category IA
V.B. Contact PrecautionsV.B.1. Use Contact Precautions as recommended
in Appendix A for patients with known orsuspected infections or evidence of syn-dromes that represent an increased risk forcontact transmission. For specific recom-mendations for use of Contact Precautionsfor colonization or infection with MDROs,consult the MDRO guideline, available athttp://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline2006.pdf.869
V.B.2. Patient placementV.B.2.a. In acute care hospitals, place patients
who require Contact Precautions in asingle-patient room when avail-able.24,686,792,795,796,805,836,892,1010,1011
Category IBV.B.2.b. When single-patient rooms are in
short supply, apply the followingprinciples for making decisions onpatient placement:
d Prioritize patients with conditions thatmay facilitate transmission (eg, uncon-tained drainage, stool incontinence) forsingle-patient room placement. Cate-gory II
d Place patients who are infected or col-onized with the same pathogen andare suitable roommates together inthe same room (cohort).29,637,807,810-
d If it becomes necessary to place a pa-tient requiring Contact Precautions ina room with a patient who is not in-fected or colonized with the same in-fectious agent:
- Avoid placing patients on Contact Pre-cautions in the same room with pa-tients who have conditions that mayincrease the risk of adverse outcomefrom infection or that may facilitatetransmission (eg, those who are im-munocompromised, have openwounds, or have anticipated pro-longed lengths of stay). Category II
- Ensure that patients are physicallyseparated (ie, .3 feet apart) fromeach other. Draw the privacy curtainbetween beds to minimize opportu-nities for direct contact. Category II
- Change protective attire and per-form hand hygiene between contactwith patients in the same room, re-gardless of whether or not either ofthe patients is on Contact Precau-tions.727,740,741,986,1012,1013 Category IB
V.B.2.c. In long-term care and other residen-tial settings, make decisions regard-ing patient placement on a case-by-case basis, balancing infection risksto other patients in the room, thepresence of risk factors that increasethe likelihood of transmission, andthe potential adverse psychologicalimpact on the infected or colonizedpatient.919,920 Category II
V.B.2.d. In ambulatory settings, place pa-tients who require Contact Precau-tions in an examination room orcubicle as soon as possible.20 Cate-gory II
V.B.3. Use of PPEV.B.3.a. GlovesWear gloves whenever touching the patient’sintact skin24,89,134,558,745,836 or surfaces andarticles in close proximity to the patient(eg, medical equipment, bed rails).72,73,88,836
Don gloves on entry into the room or cubicle.Category IBV.B.3.b. Gowns
V.B.3.b.i. Wear a gown whenever it is an-ticipated that clothing will comein direct contact with the pa-tient or potentially contami-nated environmental surfaces
or equipment in close proxim-ity to the patient. Don a gown onentry into the room or cubicle.Remove the gown and observehand hygiene before leavingthe patient care environ-ment.24,88,134,744,836 Category IB
V.B.3.b.ii. After gown removal, ensurethat clothing and skin do notcontact potentially contami-nated environmental surfacesthat could result in possibletransfer of microorganism toother patients or environmen-tal surfaces.72,73 Category II
V.B.4. Patient transportV.B.4.a. In acute care hospitals and long-
term care and other residential set-tings, limit transport and movementof patients outside of the room tomedically necessary purposes. Cate-gory II
V.B.4.b. When transport or movement in anyhealth care setting is necessary, en-sure that infected or colonized areasof the patient’s body are containedand covered. Category II
V.B.4.c. Remove and dispose of contami-nated PPE and perform hand hy-giene before transporting patientson Contact Precautions. Category II
V.B.4.d. Don clean PPE to handle the patientat the transport destination. Cate-gory II
V.B.5. Patient care equipment and instruments/devicesV.B.5.a. Handle patient care equipment and
instruments/devices according toStandard Precautions.738,835 Cate-gory IB/IC
V.B.5.b. In acute care hospitals and long-term care and other residential set-tings, use disposable noncriticalpatient care equipment (eg, bloodpressure cuffs) or implement pa-tient-dedicated use of such equip-ment. If common use of equipmentfor multiple patients is unavoidable,clean and disinfect such equipmentbefore use on another pa-tient.24,88,795,835,836,853,1014 CategoryIB
V.B.5.c. In-home care settingsV.B.5.c.i. Limit the amount of nondispos-
able patient care equipment
Siegel et al December 2007 S119
brought into the home of a pa-tient on Contact Precautions.Whenever possible, leave pa-tient care equipment in thehome until discharge fromhome care services. Category II
V.B.5.c.ii. If noncritical patient careequipment (eg, stethoscope)cannot remain in the home,clean and disinfect items be-fore taking them from thehome using a low- to interme-diate-level disinfectant. Alter-natively, place contaminatedreusable items in a plastic bagfor transport and subsequentcleaning and disinfection. Cat-egory II
V.B.5.d. In ambulatory settings, place con-taminated reusable noncritical pa-tient care equipment in a plasticbag for transport to a soiled utilityarea for reprocessing. Category II
V.B.6. Environmental measuresEnsure that rooms of patients on Contact Precau-tions are prioritized for frequent cleaning and dis-infection (eg, at least daily) with a focus onfrequently touched surfaces (eg, bed rails, overbedtable, bedside commode, lavatory surfaces in pa-tient bathrooms, doorknobs) and equipment inthe immediate vicinity of the patient.11,24,88,745,836
Category IBV.B.7. Discontinue Contact Precautions after signs
and symptoms of the infection have re-solved or according to pathogen-specificrecommendations in Appendix A. CategoryIB
V.C. Droplet PrecautionsV.C.1. Use Droplet Precautions as recommended
in Appendix A for patients known or sus-pected infection with pathogens transmittedby respiratory droplets (ie, droplets . 5 m)generated by a patient who is coughing,sneezing, or talking,14,23, Steinberg, 1969#1708,41,95,103,111,112,754,755,987,1015 CategoryIB
V.C.2. Patient placementV.C.2.a. In acute care hospitals, place pa-
tients who require Droplet Precau-tions in a single-patient roomwhen available Category II
When single-patient rooms are in short sup-ply, apply the following principles whenmaking decisions on patient placement:
d Prioritize patients who have excessivecough and sputum production for sin-gle-patient room placement. CategoryII
d Place patients who are infected thesame pathogen and are suitable room-mates together in the same room (co-hort).813,815 Category IB
d If it becomes necessary to place pa-tients who require Droplet Precautionsin a room with a patient who does nothave the same infection:- Avoid placing patients on Droplet
Precautions in the same room withpatients who have conditions thatmay increase the risk of adverse out-come from infection or that may fa-cilitate transmission (eg, those whoare immunocompromised or haveanticipated prolonged lengths ofstay). Category II
- Ensure that patients are physicallyseparated (ie, .3 feet apart) fromeach other. Draw the privacy curtainbetween beds to minimize opportu-nities for close contact.103,104,409 Cat-egory IB
- Change protective attire and per-form hand hygiene between contactwith patients in the same room,regardless of whether or not eitherpatient is on Droplet Precautions.740-
741,986,1012,1013 Category IBV.C.2.b. In long-term care and other residen-
tial settings, make decisions reg-arding patient placement on acase-by-case basis after consideringinfection risks to other patients inthe room and available alterna-tives.409 Category II
V.C.2.c. In ambulatory settings, place pa-tients who require Droplet Precau-tions in an examination room orcubicle as soon as possible. Instructpatients to follow recommendationsfor respiratory hygiene/cough eti-quette.9,446,447,827 Category II
V.C.3. Use of PPEV.C.3.a. Don a mask on entry into the patient’s
room or cubicle.14,23,41,103,111,113,115,
826 Category IBV.C.3.b. No recommendation for routinely
wearing eye protection (eg, goggleor face shield) in addition to amask, for close contact with patients
S120 Vol. 35 No. 10 Supplement 2 Siegel et al
who require Droplet Precautions.Unresolved issue
V.C.3.c. For patients with suspected orproven SARS, avian influenza orpandemic influenza, refer to the fol-lowing websites for the most currentrecommendations: http://www.cdc.gov/ncidod/sars/; http://www.cdc.gov/flu/avian/; and http://www.pandemicflu.gov/.134,1016,1017
V.C.4. Patient transportV.C.4.a. In acute care hospitals and long-
term care and other residential set-tings, limit transport and movementof patients outside of the room tomedically necessary purposes. Cate-gory II
V.C.4.b. If transport or movement in anyhealth care setting is necessary, in-struct the patient to wear a maskand follow respiratory hygiene/cough etiquette (see http://www.cdc.gov/flu/professionals/infectioncontrol/resphygiene.htm). Category IB
V.C.4.c. No mask is required for personstransporting patients on DropletPrecautions. Category II
V.C.4.d. Discontinue Droplet Precautionsafter signs and symptoms haveresolved or according to pathogen-specific recommendations in Ap-pendix A. Category IB
V.D. Airborne PrecautionsV.D.1. Use Airborne Precautions as recommended
in Appendix A for patients known or sus-pected to be infected with infectious agentstransmitted person to person by the air-borne route (eg, M tuberculosis,12 mea-sles,34,122,1018 chickenpox,123,772,1019
disseminated herpes zoster1020). CategoryIA/IC
V.D.2. Patient placementV.D.2.a. In acute care hospitals and long-
term care settings, place patientswho require Airborne Precautionsin an AIIR that has been constructedin accordance with current guide-lines.11-13 Category IA/IC
V.D.2.a.i. Provide at least 6 (in an existingfacility) or 12 (in new construc-tion/renovation) air changesper hour.
V.D.2.a.ii. Direct exhaust of air to the out-side. If it is not possible to
exhaust air from an AIIR di-rectly to the outside, the airmay be returned to the air-handling system or adjacentspaces if all air is directedthrough HEPA filters.
V.D.2.a.iii. Whenever an AIIR is in use fora patient on Airborne Precau-tions, monitor air pressuredaily with visual indicators(eg, smoke tubes, flutterstrips), regardless of the pres-ence or absence of differentialpressure-sensing devices (eg,manometers).11,12,1021,1022
V.D.2.a.iv. Keep the AIIR door closedwhen not required for entryand exit.
V.D.2.b. When an AIIR is not available, trans-fer the patient to a facility that hasan available AIIR.12 Category II
V.D.2.c. In the event of an outbreak or expo-sure involving large numbers of pa-tients who require AirbornePrecautions:
d Consult an ICP before patient place-ment to determine the safety of an al-ternative room that does not meetengineering requirements for an AIIR.
d Place patients who are presumed tohave the same infection (based on clin-ical presentation and diagnosis whenknown) together (cohort) in areas ofthe facility away from other patients,especially patients at increased riskfor infection (eg, immunocompro-mised patients).
d Use temporary portable solutions (eg,exhaust fan) to create a negative-pres-sure environment in the convertedarea of the facility. Discharge air di-rectly to the outside, away from peopleand air intakes, or direct all of the airthrough HEPA filters before it is intro-duced to other air spaces.12 Category II
V.D.2.d. In ambulatory settings:V.D.2.d.i. Develop systems (eg, triage,
signage) to identify patientswith known or suspected infec-tions who require AirbornePrecautions on entry into am-bulatory settings.9,12,34,127,134
Category IAV.D.2.d.ii. Place the patient in an AIIR as
not available, place a surgicalmask on the patient and placethe patient in an examinationroom. Once the patient leaves,the room should remain va-cant for the appropriate time(generally 1 hour) to allow fora full exchange of air.11,12,122
Category IB/ICV.D.2.d.iii. Instruct a patient with a known
or suspected airborne infec-tion to wear a surgical maskand observe respiratory hy-giene/cough etiquette. Once inan AIIR, the mask may be re-moved; the mask should re-main on if the patient is not inan AIIR.12,107,145,898 CategoryIB/IC
V.D.3. Personnel restrictionsRestrict susceptible HCWs from entering therooms of patients known or suspected to havemeasles (rubeola), varicella (chickenpox), dissemi-nated zoster, or smallpox if other immune HCWsare available.17,774 Category IBV.D.4. Use of PPE
V.D.4.a. Wear a fit-tested NIOSH-approvedN95 or higher-level respirator forrespiratory protection when enter-ing the room or home of a patientwhen the following diseases aresuspected or confirmed:
d Infectious pulmonary or laryngeal tu-berculosis, or when infectious tubercu-losis skin lesions are present andprocedures that would aerosolize via-ble organisms (eg, irrigation, incisionand drainage, whirlpool treatments)are performed.12,1023,1024 Category IB
d Smallpox (vaccinated and unvacci-nated). Respiratory protection is rec-ommended for all HCWs, includingthose with a documented ‘‘take’’ aftersmallpox vaccination due to the riskof a genetically engineered virusagainst which the vaccine may not pro-vide protection, or of exposure to avery large viral load (from, eg, high-risk aerosol-generating procedures,immunocompromised patients, hem-orrhagic or flat smallpox).108,129
Category IIV.D.4.b. No recommendation is made re-
garding the use of PPE by HCWswho are presumed to be immune
to measles (rubeola) or varicella-zoster based on history of disease,vaccine, or serologic testing whencaring for an individual with knownor suspected measles, chickenpox,or disseminated zoster due to diffi-culties in establishing definite im-munity.1025,1026 Unresolved issue
V.D.4.c. No recommendation is made re-garding the type of PPE (ie, surgicalmask or respiratory protection witha N95 or higher-level respirator) tobe worn by susceptible HCWs whomust have contact with patientswith known or suspected measles,chickenpox, or disseminated herpeszoster. Unresolved issue
V.D.5. Patient transportV.D.5.a. In acute care hospitals and long-
term care and other residential set-tings, limit transport and movementof patients outside of the room tomedically necessary purposes. Cate-gory II
V.D.5.b. If transport or movement outside anAIIR is necessary, instruct the patientto wear a surgical mask, if possible,and to observe respiratory hygiene/cough etiquette.12 Category II
V.D.5.c. For a patient with skin lesions asso-ciated with varicella or smallpox ordraining skin lesions caused by Mtuberculosis, cover the affectedareas to prevent aerosolization orcontact with the infectious agentin skin lesions.108,1023,1024,1027-1029
Category IBV.D.5.d. An HCW transporting a patient on
Airborne Precautions does notneed to wear a mask or respiratorduring transport if the patient iswearing a mask and infectious skinlesions are covered. Category II
V.D.6. Exposure managementImmunize or provide the appropriate immuneglobulin to susceptible persons as soon as possibleafter unprotected contact (ie, exposure) to a pa-tient with measles, varicella, or smallpox: CategoryIA
d Administer measles vaccine to exposedsusceptible persons within 72 hours afterthe exposure or administer immune globu-lin within 6 days of the exposure event forhigh-risk persons in whom vaccine is con-traindicated.17,1030-1033
S122 Vol. 35 No. 10 Supplement 2 Siegel et al
d Administer varicella vaccine to exposedsusceptible persons within 120 hours afterthe exposure or administer varicella im-mune globulin (VZIG or an alternative pro-duct), when available, within 96 hours forhigh-risk persons in whom vaccine is con-traindicated (eg, immunocompromisedpatients, pregnant women, newbornswhose mother’s varicella onset was , 5days before or within 48 hours after deliv-ery).887,1033-1035
d Administer smallpox vaccine to exposedsusceptible persons within 4 days after ex-posure.108,1036-1038
V.D.7. Discontinue Airborne Precautions accord-ing to pathogen-specific recommendationsin Appendix A. Category IB
V.D.8. Consult the Guidelines for Preventing theTransmission of Mycobacterium tuberculosisin Health Care Settings, 200512 and theGuideline for Environmental Infection Con-trol in Health Care Facilities11 for additionalguidance on environment strategies for pre-venting transmission of tuberculosis inhealth care settings. The environmental rec-ommendations in these guidelines may beapplied to patients with other infectionsthat necessitate Airborne Precautions.
VI. Protective Environment (see Table 4)
VI.A. Place allogeneic HSCT patients in a PE as de-scribed in the Guideline to Prevent OpportunisticInfections in HSCT Patients,15 Guideline for Envi-ronmental Infection Control in Health Care Facili-ties,11 and Guidelines for Preventing HealthCare–Associated Pneumonia, 200314 to reduce ex-posure to environmental fungi (eg, Aspergillusspp).157,158 Category IB
VI.B. No recommendation for placing patients withother medical conditions associated with in-creased risk for environmental fungal infections(eg, aspergillosis) in a PE.11 Unresolved issue
VI.C. For patients who require a PE, implement the fol-lowing (see Table 5):11,15
VI.C.1. Environmental controlsVI.C.1.a. Filtered incoming air using central
or point-of-use HEPA filters capableof removing 99.97% of particles $
0.3 mm in diameter.13 Category IBVI.C.1.b. Directed room airflow with the air
supply on one side of the room thatmoves air across the patient bed andout through an exhauston the oppo-site side of the room.13 Category IB
VI.C.1.c. Positive air pressure in room rela-tive to the corridor (pressure differ-ential of $ 12.5 Pa0.01-in water
gauge).13 Category IBVI.C.1.c.i. Monitor air pressure daily with
visual indicators (eg, smoketubes, flutter strips).11,1022 Cat-egory IA
VI.C.1.d. Well-sealed rooms that prevent in-filtration of outside air.13 CategoryIB
VI.C.1.e. At least 12 air changes per hour.13
Category IBVI.C.2. Lower dust levels by using smooth, nonpo-
rous surfaces and finishes that can bescrubbed, rather than textured material(eg, upholstery). Wet dust horizontal sur-faces whenever dust detected and routinelyclean crevices and sprinkler heads wheredust may accumulate.939,940 Category II
VI.C.3. Avoid carpeting in hallways and patientrooms in areas.940 Category IB
VI.C.4. Prohibit dried and fresh flowers and pottedplants.940-942 Category II
VI.D. Minimize the time that patients who require a PEare outside their rooms for diagnostic proceduresand other activities.11,158,944 Category IB
VI.E. During periods of construction, to prevent inhala-tion of respirable particles that could contain in-fectious spores, provide respiratory protection(eg, N95 respirator) to patients who are medicallyfit to tolerate a respirator when they are requiredto leave the PE.158,944 Category II
VI.E.1.a. No recommendation for fit testing of pa-tients who are using respirators. Unre-solved issue
VI.E.1.b. No recommendation for use of particu-late respirators when leaving the PE inthe absence of construction. Unresolvedissue
VI.F. Use of Standard and Transmission-Based Precau-tions in a PE
VI.F.1. Use Standard Precautions as recommendedfor all patient interactions. Category IA
VI.F.2. Implement Droplet and Contact Precau-tions as recommended for diseases listedin Appendix A. Transmission-Based precau-tions for viral infections may need to beprolonged because of the patient’s immu-nocompromised state and prolonged shed-ding of viruses.927,929,931,1008,1009 CategoryIB
VI.F.3. Barrier precautions, (eg, masks, gowns,gloves) are not required for HCWs in the ab-sence of suspected or confirmed infection
Siegel et al December 2007 S123
in the patient or if they are not indicated ac-cording to Standard Precautions.15 CategoryII
VI.F.4. Implement Airborne Precautions for pa-tients who require a PE and who also havean airborne infectious disease (eg, pulmo-nary or laryngeal tuberculosis, acute vari-cella-zoster). Category IA
VI.F.4.a. Ensure that the PE is designed tomaintain positive pressure.13 Cate-gory IB
VI.F.4.b. Use an anteroom to further supportthe appropriate air balance relativeto the corridor and the PE; provideindependent exhaust of contami-nated air to the outside or place aHEPA filter in the exhaust duct ifthe return air must be recircu-lated.13,1039 Category IB
VI.F.4.c. If an anteroom is not available,place the patient in an AIIR anduse portable, industrial-grade HEPAfilters in the room to enhance filtra-tion of spores.1040 Category II
GLOSSARY
Airborne infection isolation room (AIIR). Formerlyknown as a negative-pressure isolation room, an AIIRis a single-occupancy patient care room used to isolatepersons with a suspected or confirmed airborne infec-tious disease. Environmental factors are controlled inAIIRs to minimize the transmission of infectious agentsthat are usually transmitted from person to person bydroplet nuclei associated with coughing or aerosoliza-tion of contaminated fluids. AIIRs should provide neg-ative pressure in the room (so that air flows under thedoor gap into the room), an air flow rate of 6 to 12air changes per hour (ACH) (6 ACH for existing struc-tures, 12 ACH for new construction or renovation),and direct exhaust of air from the room to the outsideof the building or recirculation of air through a high-efficiency particulate air filter before returning tocirculation. (MMWR 2003; 52 [RR-10]; MMWR 1994;43 [RR-13).]
American Institute of Architects (AIA). A profes-sional organization that has developed standards forbuilding ventilation, the 2001Guidelines for Design andConstruction of Hospital and Health Care Facilities, thedevelopment of which was supported by the AIA, Acad-emy of Architecture for Health, and Facilities GuidelineInstitute, with assistance from the US Department ofHealth and Human Services and the National Institutesof Health, is the primary source of guidance for
creating airborne infection isolation rooms and protec-tive environments (http://www.aia.org/aah).
Ambulatory care setting. A facility that provideshealth care to patients who do not remain overnight;examples include hospital-based outpatient clinics,non–hospital-based clinics and physician offices, ur-gent care centers, surgicenters, free-standing dialysiscenters, public health clinics, imaging centers, ambula-tory behavioral health and substance abuse clinics,physical therapy and rehabilitation centers, and dentalpractices.
Bioaerosol. An airborne dispersion of particles con-taining whole or parts of biological entities, includingbacteria, viruses, dust mites, fungal hyphae, and fungalspores. Such aerosols usually consist of a mixture ofmonodispersed and aggregate cells, spores, or virusescarried by other materials, such as respiratory secre-tions and/or inert particles. Infectious bioaerosols (ie,those containing biological agents capable of causingan infectious disease) can be generated from humansources (eg, expulsion from the respiratory tract duringcoughing, sneezing, talking, singing, suctioning, orwound irrigation), wet environmental sources (eg,high-volume air consitioning and cooling tower waterwith Legionella) or dry sources (eg, construction dustwith spores produced by Aspergillus spp). Bioaerosolsinclude large respiratory droplets and small droplet nu-clei (Cole EC. AJIC 1998;26: 453-64).
Caregiver.. Any person who is not an employee of anorganization, is not paid, and provides or assists in pro-viding health care to a patient (eg, family member,friend) and acquire technical training as needed basedon the tasks that must be performed.
Cohorting. In the context of this guideline, this termapplies to the practice of grouping patients infected orcolonized with the same infectious agent together toconfine their care to one area and prevent contactwith susceptible patients (cohorting patients). Duringoutbreaks, health care personnel may be assigned toa cohort of patients to further limit opportunities fortransmission (cohorting staff).
Colonization. Proliferation of microorganisms on orwithin body sites without detectable host immune re-sponse, cellular damage, or clinical expression. Thepresence of a microorganism within a host may occurwith varying durations but may become a source of po-tential transmission. In many instances, colonizationand carriage are synonymous.
Droplet nuclei. Microscopic particles , 5 mm in sizethat are the residue of evaporated droplets and are pro-duced when a person coughs, sneezes, shouts, or sings.These particles can remain suspended in the air forprolonged periods and can be carried on normal aircurrents in a room or beyond, to adjacent spaces orareas receiving exhaust air.
Engineering controls. Removal or isolation of aworkplace hazard through technology. An airborne in-fection isolation room, a protective environment, engi-neered sharps injury prevention device, and a sharpscontainer are examples of engineering controls.
Epidemiologically important pathogen. An infec-tious agent that has one or more of the following char-acteristics: (1) readily transmissible, (2) a proclivitytoward causing outbreaks, (3) possible associationwith a severe outcome, and (4) difficult to treat. Exam-ples include Acinetobacter spp, Aspergillus spp, Burk-holderia cepacia, Clostridium difficile, Klebsiella orEnterobacter spp, extended-spectrum beta-lactamase–producing gram-negative bacilli, methicillin-resistantStaphylococcus aureus, Pseudomonas aeruginosa, van-comycin-resistant enterococci, vancomycin-resistantStaphylococcus aureus, influenza virus, respiratory syn-cytial virus, rotavirus, severe acute respiratory syn-drome coronavirus, noroviruses, and the hemorrhagicfever viruses.
Hand hygiene. A general term that applies to anyone of the following: (1) handwashing with plain (non-antimicrobial) soap and water, (2) antiseptic handwash-ing (soap containing antiseptic agents and water), (3)antiseptic handrub (waterless antiseptic product,most often alcohol-based, rubbed on all surfaces ofhands), or (4) surgical hand antisepsis (antiseptic hand-wash or antiseptic handrub performed preoperativelyby surgical personnel to eliminate transient hand floraand reduce resident hand flora).558
Health care–associated infection (HAI). An infec-tion that develops in a patient who is cared for in anysetting where health care is delivered (eg, acute carehospital, chronic care facility, ambulatory clinic, dialy-sis center, surgicenter, home) and is related to receivinghealth care (ie, was not incubating or present at thetime health care was provided). In ambulatory andhome settings, HAI refers to any infection that is asso-ciated with a medical or surgical intervention. Becausethe geographic location of infection acquisition is oftenuncertain, the preferred term is considered to be healthcare-associated rather than health care-acquired.
Healthcare epidemiologist. A person whose pri-mary training is medical (MD, DO) and/or masters- ordoctorate-level epidemiology who has received ad-vanced training in health care epidemiology. Typicallythese professionals direct or provide consultation to aninfection control program in a hospital, long-term carefacility, or health care delivery system (also see Infec-tion control professional).
Health care personnel, health care worker (HCW).Any paid or unpaid person who works in a healthcare setting (eg, any person who has professional ortechnical training in a health care–related field andprovides patient care in a health care setting or any
person who provides services that support the deliveryof health care such as dietary, housekeeping, engineer-ing, maintenance personnel).
Hematopoietic stem cell transplantation (HSCT).Any transplantation of blood- or bone marrow–derivedhematopoietic stem cells, regardless of donor type (eg,allogeneic or autologous) or cell source (eg, bone mar-row, peripheral blood, or placental/umbilical cordblood), associated with periods of severe immunosup-pression that vary with the source of the cells, the in-tensity of chemotherapy required, and the presenceof graft versus host disease (MMWR 2000; 49: RR-10).
High-efficiency particulate air (HEPA) filter. An airfilter that removes .99.97% of particles . 0.3 mm(the most penetrating particle size) at a specified flowrate of air. HEPA filters may be integrated into the cen-tral air handling systems, installed at the point of useabove the ceiling of a room, or used as portable units(MMWR 2003; 52: RR-10).
Home care. A wide range of medical, nursing, reha-bilitation, hospice, and social services delivered to pa-tients in their place of residence (eg, privateresidence, senior living center, assisted living facility).Home health care services include care provided byhome health aides and skilled nurses, respiratory ther-apists, dieticians, physicians, chaplains, and volun-teers; provision of durable medical equipment; homeinfusion therapy; and physical, speech, and occupa-tional therapy.
Immunocompromised patient. A patient whose im-mune mechanisms are deficient because of a congeni-tal or acquired immunologic disorder (eg, humanimmunodeficiency virus infection, congenital immunedeficiency syndromes), chronic diseases such as diabe-tes mellitus, cancer, emphysema, or cardiac failure, in-tensive care unit care, malnutrition, andimmunosuppressive therapy of another disease pro-cess [eg, radiation, cytotoxic chemotherapy, anti–graftrejection medication, corticosteroids, monoclonal anti-bodies directed against a specific component of the im-mune system]). The type of infections for which animmunocompromised patient has increased suscepti-bility is determined by the severity of immunosuppres-sion and the specific component(s) of the immunesystem that is affected. Patients undergoing allogeneichematopoietic stem cell transplantation and those withchronic graft versus host disease are considered themost vulnerable to health care–associated infections.Immunocompromised states also make it more diffi-cult to diagnose certain infections (eg, tuberculosis)and are associated with more severe clinical diseasestates than persons with the same infection and a nor-mal immune system.
Infection. The transmission of microorganisms intoa host after evading or overcoming defense
Siegel et al December 2007 S125
mechanisms, resulting in the organism’s proliferationand invasion within host tissue(s). Host responses to in-fection may include clinical symptoms or may be sub-clinical, with manifestations of disease mediated bydirect organisms pathogenesis and/or a function ofcell-mediated or antibody responses that result in thedestruction of host tissues.
Infection control and prevention professional(ICP). A person whose primary training is in eithernursing, medical technology, microbiology, or epide-miology and who has acquired specialized training ininfection control. Responsibilities may include collec-tion, analysis, and feedback of infection data andtrends to health care providers; consultation on infec-tion risk assessment, prevention, and control strate-gies; performance of education and training activities;implementation of evidence-based infection controlpractices or those mandated by regulatory and licens-ing agencies; application of epidemiologic principlesto improve patient outcomes; participation in planningrenovation and construction projects (eg, to ensureappropriate containment of construction dust); evalua-tion of new products or procedures on patient out-comes; oversight of employee health services relatedto infection prevention; implementation of prepared-ness plans; communication within the health care set-ting, with local and state health departments, and withthe community at large concerning infection control is-sues; and participation in research. Certification in in-fection control is available through the CertificationBoard of Infection Control and Epidemiology.
Infection control and prevention program. A multi-disciplinary program that includes a group of activitiesto ensure that recommended practices for the preven-tion of health care–associated infections are imple-mented and followed by health care workers, makingthe health care setting safe from infection for patientsand health care personnel. The Joint Commission onAccreditation of Healthcare Organizations requiresthe following 5 components of an infection controlprogram for accreditation: (1) surveillance: monitoringpatients and health care personnel for acquisition of in-fection and/or colonization; (2) investigation: identifica-tion and analysis of infection problems or undesirabletrends; (3) prevention: implementation of measures toprevent transmission of infectious agents and to reducerisks for device- and procedure-related infections; (4)control: evaluation and management of outbreaks;and (5) reporting: provision of information to externalagencies as required by state and federal laws and reg-ulations (see http://www.jcaho.org). The infection con-trol program staff has the ultimate authority todetermine infection control policies for a health careorganization with the approval of the organization’sgoverning body.
Long-term care facility (LTCF). A residential or outpa-tient facility designed to meet the biopsychosocialneeds of persons with sustained self-care deficits.These include skilled nursing facilities, chronic diseasehospitals, nursing homes, foster and group homes, in-stitutions for the developmentally disabled, residentialcare facilities, assisted living facilities, retirementhomes, adult day health care facilities, rehabilitationcenters, and long-term psychiatric hospitals.
Mask. A term that applies collectively to items usedto cover the nose and mouth and includes both proce-dure masks and surgical masks (see http://www.fda.gov/cdrh/ode/guidance/094.html#4).
Multidrug-resistant organism (MDRO). In general, abacterium (excluding Mycobacterium tuberculosis) thatis resistant to 1 or more classes of antimicrobial agentsand usually is resistant to all but 1 or 2 commerciallyavailable antimicrobial agents (eg, methicillin-resistantStaphylococcus aureus, vancomycin-resistant entero-cocci, extended-spectrum beta-lactamase–producingor intrinsically resistant gram-negative bacilli).176
Nosocomial infection. Derived from 2 Greek words,‘‘nosos’’ (disease) and ‘‘komeion’’ (to take care of), re-fers to any infection that develops during or as a resultof an admission to an acute care facility (hospital) andwas not incubating at the time of admission.
Personal protective equipment (PPE). A variety ofbarriers used alone or in combination to protect mu-cous membranes, skin, and clothing from contactwith infectious agents. PPE includes gloves, masks, res-pirators, goggles, face shields, and gowns.
Procedure mask. A covering for the nose and mouththat is intended for use in general patient care situa-tions. These masks generally attach to the face withear loops rather than ties or elastic. Unlike surgicalmasks, procedure masks are not regulated by theFood and Drug Administration.
Protective environment. A specialized patient carearea, usually in a hospital, with a positive air flow rel-ative to the corridor (ie, air flows from the room to theoutside adjacent space). The combination of high-effi-ciency particulate air filtration, high numbers (.12)of air changes per hour, and minimal leakage of airinto the room creates an environment that can safelyaccommodate patients with a severely compromisedimmune system (eg, those who have received alloge-neic hemopoietic stem cell transplantation) and de-crease the risk of exposure to spores produced byenvironmental fungi. Other components include useof scrubbable surfaces instead of materials such asupholstery or carpeting, cleaning to prevent dust ac-cumulation, and prohibition of fresh flowers or pottedplants.
Quasi-experimental study. A study undertaken toevaluate interventions but do not use randomization
as part of the study design. These studies are also re-ferred to as nonrandomized, pre-/postinterventionstudy designs. These studies aim to demonstrate cau-sality between an intervention and an outcome butcannot achieve the level of confidence concerning anattributable benefit obtained through a randomizedcontrolled trial. In hospitals and public health settings,randomized control trials often cannot be imple-mented due to ethical, practical, and urgency reasons;therefore, quasi-experimental design studies are com-monly used. However, even if an intervention appearsto be effective statistically, the question can be raisedas to the possibility of alternative explanations for theresult. Such a study design is used when it is not logis-tically feasible or ethically possible to conduct a ran-domized controlled trial, (eg, during outbreaks).Within the classification of quasi-experimental studydesigns, there is a hierarchy of design features thatmay contribute to validity of results (Harris et al. CID2004:38: 1586).
Residential care setting. A facility in which peoplelive, minimal medical care is delivered, and the psycho-social needs of the residents are provided for.
Respirator. A personal protective device worn byhealth care personnel over the nose and mouth to pro-tect them from acquiring airborne infectious diseasesdue to inhalation of infectious airborne particles , 5mm in size. These include infectious droplet nucleifrom patients with Mycobacterium tuberculosis, variolavirus [smallpox], or severe acute respiratory syndromeand dust particles that contain infectious particles,such as spores of environmental fungi (eg, Aspergillusspp). The Centers for Disease Control and Prevention’sNational Institute for Occupational Safety and Health(NIOSH) certifies respirators used in health care set-tings (see http://www.cdc.gov/niosh/topics/respirators/).The N95 disposable particulate, air-purifying respira-tor is the type used most commonly by health care per-sonnel. Other respirators used include N-99 and N-100particulate respirators, powered air-purifying respira-tors with high-efficiency filters, and nonpowered full-facepiece elastomeric negative pressure respirators.A listing of NIOSH-approved respirators can be foundat http://www.cdc.gov/niosh/npptl/respirators/disp_part/particlist.html. Respirators must be used in conjunc-tion with a complete respiratory protection program,as required by the Occupational Safety and HealthAdministration, which includes fit testing, training,proper selection of respirators, medical clearance,and respirator maintenance.
Respiratory hygiene/cough etiquette. A combina-tion of measures designed to minimize the transmis-sion of respiratory pathogens through droplet orairborne routes in health care settings. The compo-nents of respiratory hygiene/cough etiquette are (1)
covering the mouth and nose during coughing andsneezing, (2) using tissues to contain respiratory secre-tions with prompt disposal into a no-touch receptacle,(3) offering a surgical mask to persons who are cough-ing to decrease contamination of the surrounding envi-ronment, and (4) turning the head away from othersand maintaining spatial separation (ideally .3 feet)when coughing. These measures are targeted to all pa-tients with symptoms of respiratory infection and theiraccompanying family members or friends beginning atthe point of initial encounter with a health care setting(eg, reception/triage in emergency departments, ambu-latory clinics, health care provider offices).126 (Sriniva-sin A ICHE 2004; 25: 1020; http://www.cdc.gov/flu/professionals/infectioncontrol/resphygiene.htm).
Safety culture. Shared perceptions of workers andmanagement regarding the level of safety in the workenvironment. A hospital safety climate includes the fol-lowing organizational components: (1) senior manage-ment support for safety programs, (2) absence ofworkplace barriers to safe work practices, (3) cleanli-ness and orderliness of the worksite, (4) minimal con-flict and good communication among staff members,(5) frequent safety-related feedback/training by super-visors, and (6) availability of PPE and engineeringcontrols.618
Source control. The process of containing an infec-tious agent either at the portal of exit from the body orwithin a confined space. The term is applied most fre-quently to containment of infectious agents transmit-ted by the respiratory route but could apply to otherroutes of transmission, (eg, a draining wound, vesicularor bullous skin lesions). Respiratory hygiene/cough et-iquette that encourages individuals to ‘‘cover yourcough’’ and/or wear a mask is a source control mea-sure. The use of enclosing devices for local exhaustventilation (eg, booths for sputum induction or admin-istration of aerosolized medication) is another exampleof source control.
Standard precautions. A group of infection preven-tion practices that apply to all patients, regardless ofsuspected or confirmed diagnosis or presumed infec-tion status. Standard precautions represents a combi-nation and expansion of universal precautions778 andbody substance isolation.1109 Standard precautionsare based on the principle that all blood, body fluids,secretions, excretions except sweat, nonintact skin,and mucous membranes may contain transmissible in-fectious agents. Standard precautions include hand hy-giene and, depending on the anticipated exposure, useof gloves, gown, mask, eye protection, or face shield. Inaddition, equipment or items in the patient environ-ment likely to have been contaminated with infectiousfluids must be handled in a manner to prevent trans-mission of infectious agents (eg, wear gloves for
handling, contain heavily soiled equipment, properlyclean and disinfect or sterilize reusable equipment be-fore use on another patient).
Surgical mask. A device worn over the mouth andnose by operating room personnel during surgical pro-cedures to protect both surgical patients and operatingroom personnel from transfer of microorganisms andbody fluids. Surgical masks also are used to protecthealth care personnel from contact with large infec-tious droplets (. 5 mm in size). According to draft guid-ance issued by the Food and Drug Administration onMay 15, 2003, surgical masks are evaluated using stan-dardized testing procedures for fluid resistance, bacte-rial filtration efficiency, differential pressure (airexchange), and flammability to mitigate the risks tohealth associated with the use of surgical masks. Thesespecifications apply to any masks that are labeledsurgical, laser, isolation, or dental or medical procedure(http://www.fda.gov/cdrh/ode/guidance/094.html#4).Surgical masks do not protect against inhalation ofsmall particles or droplet nuclei and should not be con-fused with particulate respirators that are recommen-ded for protection against selected airborne infectiousagents (eg, Mycobacterium tuberculosis).
The authors and HICPAC gratefully acknowledge Dr Larry Strausbaugh for his manycontributions and valued guidance in the preparation of this guideline.
References
1. Garner JS. Guideline for isolation precautions in hospitals. The Hos-
pital Infection Control Practices Advisory Committee. Infect Con-
1091. Drusin LM, Ross BG, Rhodes KH, Krauss AN, Scott RA. Nosoco-
mial ringworm in a neonatal intensive care unit: a nurse and her cat.
Infect Control Hosp Epidemiol 2000;21:605-7.
1092. Lewis SM, Lewis BG. Nosocomial transmission of Trichophyton ton-
surans tinea corporis in a rehabilitation hospital. Infect Control
Hosp Epidemiol 1997;18:322-5.
1093. Saiman L, Jakob K, Holmes KW, et al. Molecular epidemiology of
staphylococcal scalded skin syndrome in premature infants. Pediatr
Infect Dis J 1998;17:329-34.
1094. Ramage L, Green K, Pyskir D, Simor AE. An outbreak of fatal nos-
ocomial infections due to group A streptococcus on a medical
ward. Infect Control Hosp Epidemiol 1996;17:429-31.
1095. Kakis A, Gibbs L, Eguia J, et al. An outbreak of group A streptococcal
infection among health care workers. Clin Infect Dis 2002;35:1353-9.
1096. Schwartz B, Elliott JA, Butler JC, et al. Clusters of invasive group A
streptococcal infections in family, hospital, and nursing home set-
tings. Clin Infect Dis 1992;15:277-84.
1097. National Communicable Disease Center. Isolation techniques for use
in hospitals. Washington, DC: US Government Printing Office; 1970.
1098. Centers for Disease Control and Prevention. Isolation techniques
for use in hospitals. 2nd ed. Washington, DC: US Government
Printing Office; 1975.
1099. Garner JS, Simmons BP. CDC guideline for isolation precautions in
hospitals. Atlanta (GA): US Department of Health and Human Ser-
vices, Public Health Service, Centers for Disease Control; 1983.
1100. Lynch P, Jackson MM, Cummings MJ, Stamm WE. Rethinking the
role of isolation practices in the prevention of nosocomial infec-
tions. Ann Intern Med 1987;107:243-6.
APPENDIX A: TYPE AND DURATION OFPRECAUTIONS RECOMMENDED FOR SELECTEDINFECTIONS AND CONDITIONS
Preamble
The mode(s) and risk of transmission for each spe-cific disease agent listed in this appendix were re-viewed. Principle sources consulted for thedevelopment of disease-specific recommendations forthe appendix included infectious disease manuals andtextbooks.831,1039,1040 The published literature wassearched for evidence of person-to-person transmissionin health care and non–health care settings with a focuson reported outbreaks that would assist in developingrecommendations for all settings where health care isdelivered. The following criteria were used to assigntransmission-based precautions categories:
d A transmission-based precautions category was as-signed if there was strong evidence for person-to-per-son transmission via droplet, contact, or airborneroutes in health care or non–health care settingsand/or if patient factors (eg, diapered infants, diar-rhea, draining wounds) increased the risk oftransmission.
d Transmission-based precautions categoryassignmentsreflect the predominant mode(s) of transmission.
d If there was no evidence for person-to-person trans-mission by droplet, contact or airborne routes, thenStandard Precautions were assigned.
d If there was a low risk for person-to-person transmis-sion and no evidence of health care-associated trans-mission, then Standard Precautions were assigned.
d Standard precautions were assigned for bloodbornepathogens (eg, HBV, HCV, HIV) in accordance withCDC recommendations for universal precautions is-sued in 1988.778 Subsequent experience has confirmedthe efficacy of Standard Precautions to prevent expo-sure to infected blood and body fluid.776,777,863
Additional information relevant to use of precau-tions was added in the comments column to assistthe caregiver in decision-making. Citations were addedas needed to support a change in or provide additionalevidence for recommendations for a specific diseaseand for new infectious agents (eg, SARS-CoV, avian in-fluenza) that have been added to Appendix A. Thereader may refer to more detailed discussion concern-ing modes of transmission and emerging pathogens inthe background text and for MDRO control in theMDRO Guideline.
Siegel et al December 2007 S153
Appendix A. Continued.
Precaution
Infection/Condition Type* Durationy Comments
Abscess
Draining, major C DI No dressing or containment of drainage; until drainage stops or can be contained by
dressing.
Draining, minor or limited S Dressing to cover and contain drainage.
AIDS/HIV S Postexposure chemoprophylaxis for some blood exposures.865
Actinomycosis S Not transmitted from person to person.
Adenovirus infection (see
agent-specific guidance under
gastroenteritis, conjuctivitis,
pneumonia)
Amebiasis S Person-to-person transmission is rare. Transmission in settings for the mentally challenged
and in a family group has been reported.1041 Use care when handling diapered infants and
mentally challenged persons.1042
Anthrax S Infected patients do not generally pose a transmission risk.
Cutaneous S Transmission through nonintact skin contact with draining lesions possible; thus, use
Contact Precautions if a large amount of uncontained drainage is present. Handwashing
with soap and water is preferable to the use of waterless alcohol-based antiseptics,
because alcohol does not have sporicidal activity.979
Pulmonary S Not transmitted from person to person.
Environmental: aerosolizable
spore-containing powder or
other substance
DE Until decontamination of environment complete.203 Wear respirator (N95 mask or PAPR),
protective clothing; decontaminate persons with powder on them (http://www.cdc.gov/
mmwr/preview/mmwrhtml/mm5135a3.htm).
Hand hygiene: Handwashing for 30 to 60 seconds with soap and water or 2%
chlorhexidene gluconate after spore contact. (Alcohol handrubs are inactive against
spores.)979
Postexposure prophylaxis after environmental exposure: 60 days of antimicrobials (either
doxycycline, ciprofloxacin, or levofloxacin) and postexposure vaccine under IND.
Antibiotic-associated colitis
(see Clostridium difficile)
Arthropod-borne viral
encephalitides (eastern, west-
ern, Venezuelan equine enceph-
alomyelitis; St Louis, California
encephalitis; west Nile virus)
and viral fevers (dengue, yellow
fever, Colorado tick fever)
S Not transmitted from person to person except rarely by transfusion, and for West Nile
virus by organ transplant, breastmilk or transplacentally.528,1043 Install screens in
windows and doors in endemic areas.
Use DEET-containing mosquito repellants and clothing to cover extremities.
Ascariasis S Not transmitted from person to person.
Aspergillosis S Institute Contact Precautions and Airborne Precautions if massive soft tissue infection with
copious drainage and repeated irrigations required.154
Avian influenza (see influenza,
avian below)
Babesiosis S Not transmitted from person to person except rarely by transfusion.
Blastomycosis, North
American, cutaneous or
pulmonary
S Not transmitted from person to person.
Botulism S Not transmitted from person to person.
Bronchiolitis (see respiratory
infections in infants and
young children)
C DI Use mask according to Standard Precautions.
Brucellosis (undulant, Malta,
Mediterranean fever)
S Not transmitted from person to person except rarely through banked spermatozoa and
sexual contact.1044,1045 Provide antimicrobial prophylaxis following laboratory
Blepharitis or conjunctivitis S/C Use Contact Precautions if copious drainage is present.
Iritis or keratitis S
Vaccinia-associated erythema
multiforme (Stevens-Johnson
syndrome)
S Not an infectious condition.
Secondary bacterial infection
(eg, S. aureus, group A beta
hemolytic streptococcus
S/C Follow organism-specific (streptococcal and staphylococcal most frequent)
recommendations and consider magnitude of drainage.
Varicella zoster A,C Until lesions dry
and crusted
Susceptible HCWs should not enter room if immune caregivers are available; no
recommendation for face protection of immune HCWs; no recommendation for type of
protection (ie, surgical mask or respirator) for susceptible HCWs. In an
immunocompromised host with varicella pneumonia, prolong the duration of
precautions for duration of illness. Postexposure prophylaxis: Provide postexposure
vaccine as soon as possible but within 120 hours; for susceptible exposed persons for
whom vaccine is contraindicated (immunocompromised persons, pregnant women,
newborns whose mother’s varicella onset is # 5 days before delivery or within 48 hours
after delivery) provide VZIG, when available, within 96 hours; if unavailable, use IVIG.
Provide Airborne Precautions for exposed susceptible persons and exclude exposed
susceptible health care workers beginning 8 days after first exposure until 21 days after
last exposure or 28 if received VZIG, regardless of postexposure vaccination.1032
Variola (see smallpox)
Vibrio parahaemolyticus (see
gastroenteritis)
Vincent’s angina (trench mouth) S
Viral hemorrhagic fevers due to
Lassa, Ebola, Marburg,
Crimean-Congo fever
viruses
S, D, C DI Single-patient room preferred. Emphasize: use of sharps safety devices and safe work
practices, hand hygiene; barrier protection against blood and body fluids on entry into
room (single gloves and fluid-resistant or impermeable gown, face/eye protection with
masks, goggles or face shields), and appropriate waste handling. Use N95 or higher-level
respirator when performing aerosol-generating procedures. Largest viral load in final
stages of illness when hemorrhage may occur; additional PPE, including double gloves,
leg and shoe coverings may be used, especially in resource-limited settings where
options for cleaning and laundry are limited. Notify public health officials immediately if
Ebola is suspected.212,313,738,770 Also see Table 3 for Ebola as a bioterrorism agent.
Viral respiratory diseases (not
covered elsewhere)
Adults S
Infants and young children
(see respiratory infectious
disease, acute)
Whooping cough (see
pertussis)
Wound infections
Major C DI No dressing or dressing does not contain drainage adequately.
Minor or limited S Dressing covers and contains drainage adequately.
Yersinia enterocolitica
gastroenteritis (see
gastroenteritis)
Zoster (varicella-zoster) (see
herpes zoster)
Zygomycosis (phycomycosis,
mucormycosis)
S Not transmitted person to person.
*Type of precautions: A, airborne precautions; C, contact; D, droplet; S, standard; when A, C, and D are specified, also use S.yDuration of precautions: CN, until off antimicrobial treatment and culture-negative; DI, duration of illness (with wound lesions, DI means until wounds stop draining); DE, until
environment completely decontaminated; U, until time specified in hours (hrs) after initiation of effective therapy; Unknown: criteria for establishing eradication of pathogen has