Health Skills I Student Lecture Packet
Feb 23, 2016
Health Skills I Student Lecture Packet
Health Skills I
Unit 101Infection Control
Objectives
• Identify the nature of microorganisms, how organisms grow, their transmission, body defenses of the human host, and related terminology
Unit 101.1Microorganisms
• Anton Van Leeuwenhoek– first observed
microorganism under a microscope in 1693
Microorganisms are Everywhere!
• inside and outside our bodies• in food, air, and water• some are useful– fermentation of food
• small percentage cause disease• organisms can be spread• healthcare workers need to understand how
to break cycle
Exciting Moments in Microbiology• Ignatz
Semmelweiss 1860
• reduced the transmission of puerperal fever by handwashing
More Exciting Moments in Microbiology
• LOUIS PASTEUR 1861
• proposed the “Germ Theory”
Definitions• Microorganism– microscopic living things that individually are
too small to be seen with the naked eye, only seen under microscope • example: germs & microbes
• Pathogen– microorganisms capable of causing disease
Definitions• Communicable disease– a pathogenic organism passed from one host
to another• Host – one infected with a pathogenic microorganism
• Susceptible host– one unable to fight off infection due to low
resistance
Definitions
• Colonized – presence of microorganisms in or on a patient,
without clinical signs and symptoms• Infection– colonization invasion of body tissues by
disease producing pathogenic microorganisms• Re-infection – infected a second time by same pathogen
Definitions
• Cross infection – spread to another person by air currents or
health worker• Co-infection – infected with more than one organism
• Secondary infection – an infection acquired following a primary
illness• Nosocomial – infection acquired within a healthcare facility.
Pathogenic OrganismsVirus
• acellular– cannot survive independently
• parasite – can only survive on living tissue– cannot be treated by antibiotics, may use
antiviral drugs– vaccinations can prevent a number of viral
infections
Pathogenic OrganismsVirus
• Examples: – polio, influenza,
common cold, HIV, Hepatitis B, mumps, herpes
Bacteriophage (virus that infects bacteria)
Pathogenic OrganismsBacteria
• simple unicellular organism– three shapes
• coccus, bacillus, spirillium
• Clostridium tetani– bacterium that causes
tetanus
Pathogenic Organisms Bacteria
• can be treated by antibiotics– examples: • strep throat, abscesses, gonorrhea, syphilis,
chlamydia, Rocky Mountain Spotted Fever, Lyme disease
• vaccinations can prevent some bacterial infections – example:• pneumonia
Pathogenic Organisms Fungi
• molds and yeast– multicellular or unicellular organisms, more
complex than bacteria
Pathogenic Organisms Fungi
• Examples: – athletes foot,
ringworm, vaginal yeast infection, thrush
Pilobolus, a fungus
Pathogenic Organisms Protozoa
• largest single celled organism• relatively few cause disease in humans• many parasites passed by insects• transmitted by food
Pathogenic Organisms Protozoa
• Examples: – malaria, dysentery,
sleeping sickness
Amoeba, a protozoan
Pathogenic OrganismsClostridium difficile
(C. difficile)
• C. difficile is: – a pathogenic species of anaerobic bacteria
causing pseudomembranous colitis and diarrhea, after receiving antibiotic therapy. This is frequent cause of nosocomial diarrhea
Definitions
• Anaerobic – a microorganism that grows and lives in the
complete or almost complete absence of oxygen
• Pseudomembranous colitis– diarrhea caused by overuse of antibiotics
transmitted by healthcare workers not washing hands properly
Pathogenic Organisms C. difficile
– common hazard of antibiotic use– most common cause of nosocomial infectious
diarrhea– may cause bleeding & bowel perforation– can exist months on environmental surfaces &
flourishes on hands of healthcare workers– At risk patients: • chemotherapy, antibiotic therapy &
gastrointestinal procedures
C. difficile
• Standards of care for patient w/ diagnosis of C. difficile– good handwashing before & after patient care
procedures– use of Standard Precaution barriers for Contact
Isolation guidelines (gown, gloves, private room)– the antibiotic related to the cause of C. difficile
will be discontinued by physician and further care will begin
Pathogenic OrganismsVancomycin Resistant Enterococcus (VRE)
• VRE is: – a bacteria that normally lives in the digestive
tract that has developed a resistance to the antibiotic vancomycin and most other antibiotics
Definitions
• Vancomycin – antibiotic used to treat strep and staph
infections• Enterococcus – any Streptococcus that inhabits the intestinal
tract
Pathogenic Organisms VRE
– caused by overuse of antibiotics– VRE infections frequently found in:
• urinary tract, at surgical sites, and in the bloodstream
– spreads through:• direct contact with a VRE infected patient• direct contact with surfaces & equipment
contaminated with VRE • hands of a healthcare worker contaminated with VRE
– lives weeks on surfaces
VRE
• At risk patients for VRE:– immunosuppressed conditions– history of vancomycin therapy– indwelling urinary or central venous catheters– elderly– abdominal surgery patients– wounds/burn victims
VRE
• Standards of Care for VRE diagnosed patients:– good handwashing before & after care– use Standard Precaution barriers and contact
Isolation Precautions – the antibiotic will be discontinued by a
physician with plan for further care
Pathogenic Organisms (MRSA)
• Methicillin Resistant Staphylococcus Aureus (MRSA) is:– bacteria that populates the skin, mucous
membranes and upper respiratory tract, the intestines and genitourinary tracts that has become resistant to the antibiotics methicillin and penicillin
Pathogenic Organisms MRSA
– endemic (expected “normal” incidence) within community & tertiary hospitals, skilled-nursing facilities & long-term care
– most frequent sites of this bacteria is the nares, groin, axilla and gut
– transmitted primarily on the hands of the healthcare workers
MRSA
• At risk patients for MRSA:– those on broad-spectrum antibiotics therapy– immunosuppressed patients– burn patients– central venous catheters– surgical wounds– prolonged hospital stays
MRSA
• Standard of care for patient w/MRSA diagnosis:– topical ointment to nostrils– if infected, vancomycin
Key FactorsC. difficile, VRE, MRSA
– handwashing & standard precautions– single room for infected/colonized patients– use antiseptic cleansers in high risk areas – daily cleansing of environmental surfaces that
have had direct hand contact
Key FactorsC. difficile, VRE, MRSA
– dedicate equipment for exclusive use for infected patient(stethoscopes, BP cuffs, etc.)
– keep equipment off bed & bed tables– provide protective gear to patient when
leaving their room (mask, gown, etc.)
Infection Cycle
• Three Elements Required:– source of infecting
microorganisms– susceptible host– mode of transmission
source
susceptible host
mode oftransmission
Infection Cycle
• Source– may include persons with acute disease– persons in the incubation period of disease– persons who are colonized by infectious agent– persons who are chronic carriers– can be inanimate objects
Infection Cycle
• Host– one infected with a pathologic microorganism– resistance varies– may develop immunity– may be an asymptomatic carrier– may develop clinical disease
Infection CycleTransmission
• May be transmitted by more than one route
• Five main routes:– contact-direct or indirect– droplet– airborne– common vehicle– vectorborne
1. Contact Transmission
• *most frequent mode of noscomial infection• Direct Contact – skin to skin
• Indirect Contact – contact with an inanimate object contaminated
by the infected patient
2. Droplet Transmission
– a form of contact transmission
– droplets are propelled a short distance (3 feet)
– droplets are deposited on hosts such as the mucous membranes of eye, nose or mouth
droplets are generated bycoughing, sneezing or talking
2. Droplet Transmission
– droplets transmitted during medical procedures of bronchoscopy or suctioning that put healthcare workers at risk
– private room ideal• Can be placed w/other similar conditions 3’ apart if
room availability is an issue– healthcare worker must wear mask when caring
for a person with droplet isolation precautions– Example: • Influenza
3. Airborne Transmission
– spreads by way of airborne droplets or dust particles containing infectious agents (microorganisms) and inhaled by the new host
– spread by air currents– special handling and ventilation required to prevent
transmission– requires private room – Examples
• tuberculosis, rubeola, and varicella (chicken pox), herpes zosters viruses spread via airborne transmission
3. Airborne Transmission
– spreads by way of airborne droplets or dust particles containing infectious agents
– spread by air currents– special handling and ventilation required to
prevent transmission– requires private room – Examples
• tuberculosis, rubeola, and varicella (chicken pox), herpes zosters viruses spread via airborne transmission
4. CommonVehicle Transmission
– microorganisms transported by contaminated food, water, medication or equipment
– Examples: • Hepatitis A, salmonella, Typhoid Fever
5. Vectorborne Transmission
– vectors transport disease• mosquitoes, flies, ticks,
rats and other vermin transmit disease
– Examples: • rabies, malaria, Rocky
Mountain FeverTick
How Microorganisms Grow in Humans
• Need:– food– oxygen
• aerobes-need oxygen• anaerobes-do not need oxygen
– temperature• 98.6 F or 36 C or warmer
– moisture– pH
• acidity or alkalinity
Natural Defenses of the Host
• Hairs– cilia
• Fluid– tears, ear wax, blood
• Skin Tissue– intact and healthy
• Proper Rest• Proper Nutrition
• Natural Immunity– childbirth & disease
process• Phagocytosis
– cells that can destroy bacteria
• Normal flora– bacteria present that do
not normally cause disease
– streptococci
Predisposing Factors for Disease
• Poor nutrition• Fatigue• Poor health habits• Pre-existing illness• Gender• Genetics• Climate/Weather• Occupational
• Age– very young– very old
• Medical treatment– chemotherapy,
radiation therapy, bone morrow transplants, immuno-suppressed conditions, indwelling catheters
Knowledge Assessment
• 1. Give the definition for microorganism.• 2. List two examples of virus, bacteria, and fungi.• 3. List the 3 required elements of the infection cycle.• 4. Compare and contrast contact, droplet, and
airborne transmission of microorganisms.• 5. List five natural defenses of the body.