9/24/2010 1 General Approach to Antimicrobial Use in the Outpatient Wound Care Setting Clinical Symposium on Advances in Skin & Wound Care October 2, 2010 Harriet Jones, MD, BSN; FAPWCA Disclosures • Speakers Bureau – Cubist Pharmaceuticals • Editorial Board Editorial Board – Today’s Wound Clinic • Graphic Pictures to Follow Objectives for Participants • Increased understanding of a bug’s life * – Laboratory identification of microorganisms encountered in the outpatient wound care setting – Continuum of organisms in wounds: colonization infection • Non‐exhaustive review antimicrobial agents – Topical S i f bl f i i i – Systemic agents favorable for use in outpatient setting • Oral • Intravenous • Personal pearls & pitfalls (PPP) • Increased appreciation for MRSA as a pathogen • Recognition that options in antimicrobial arsenal are limited – Must prescribe antimicrobial agents wisely * Credit: Disney Films
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224 Jones H - cmcgc.com · 9/24/2010 2 Micro 101 • Gram’s stain – Offer earliest information for provider – Differentiates Gram Positive Cocci (GPC’s) from
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9/24/2010
1
General Approach to Antimicrobial Use
in the Outpatient Wound Care Setting
Clinical Symposium on Advances in Skin & Wound Care
October 2, 2010
Harriet Jones, MD, BSN; FAPWCA
Disclosures
• Speakers Bureau
– Cubist Pharmaceuticals
• Editorial BoardEditorial Board
– Today’s Wound Clinic
• Graphic Pictures to Follow
Objectives for Participants
• Increased understanding of a bug’s life*– Laboratory identification of microorganisms encountered in the
outpatient wound care setting– Continuum of organisms in wounds: colonization infection
S i f bl f i i i– Systemic agents favorable for use in outpatient setting• Oral• Intravenous • Personal pearls & pitfalls (PPP)
• Increased appreciation for MRSA as a pathogen• Recognition that options in antimicrobial arsenal are limited– Must prescribe antimicrobial agents wisely
* Credit: Disney Films
9/24/2010
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Micro 101
• Gram’s stain – Offer earliest information for provider– Differentiates Gram Positive Cocci (GPC’s) from
• @ 24h if + growth on streaked plate – Coagulase test – chemical reagent– Coagulase positive = unique to Staph aureus– Coagulase negative = any other Staph spp
• Do NOT yet know if MRSA– Must assume MRSA
Process for Gram Staining
arrowscientific.com.au
Gram’s Stain showing GPC and GNC
library.med.utah.edu
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Blood Agar Plate
http://www.lexic.us/definition‐of/blood_agar
The Microbial Continuum in Wounds
• Contamination
• Colonization
• Critical Colonization
• Infection
Contamination
• Presence of non‐replicating microorganisms on the wound surface
• Occurs 100% at time of wounding
• Absence of host clinical response
• Sources:
– Skin, periwound
– Linen, devices
– Urine, stool
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Colonization
• Occurs shortly after contamination• Replicatingmicroorganisms
– superficially attached to wound surface
• Not necessarily harmful– No need for topical or systemic antibiotics– Risks development of drug resistant bacteria
• Staphylococci spp including MRSA• Staphylococci spp including MRSA
• Streptococci spp
• Pseudomonas
• Anaerobes
– Debrides
– Three forms aqueous solutions
• all bacteriocidal
Iodine cont’d
• Cadexamer iodine– 0.9% in paste or ointment– Iodine released slowly over 48h as the base absorbs wound fluid– Preferred for use in proliferative phase of healing
• Selection of dressing dependent on – Size; depth; shape; tissue characteristics; amount of exudate
Sibbald et al; Advances Skin and Wound Care 2007; 20: 549
Methylene Blue w/ Gentian Violet
Hydrofera blue
Broad spectrum Bacteriostatic Absorbs bacteria in exudate B t i l i Bacteriolysis Singlet oxygen and free radicals
Unclear effect on tissue early in healing Requires moistening prior to application and secondary dressing Dressing changed when turns light or after 72h Available in rope or sheet (can cut to fit)
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Polyhexamethylene biguanide
Combination of cationic biguanide groups interspersed between hydrophobic hexamethylene groups
Binds to negatively charged organisms Bacteriocidal
PHMB
Cell wall disruption
GNR; GPC including MRSA; VRE; molds and yeasts
Activity independent of wound fluid Biosynthesized cellulose delivers PHMB to wound
Autolytic debridement
Available in blended gauze and a nonwoven drain sponge
Maintains moisture balance
wormandflowers.wordpress.com
TOPICAL ANTIBIOTICS
• Bacitracin– Polypeptide produced by Bacillus subtilis
– A, B, C – subgroups
– A = major constituent of commercial preparationsA = major constituent of commercial preparations
– Binds to bacterial cell wall and stunts its growth
– Primarily for Staph and Strep spp
– Minor toxicity profile
• some irritation
– May cross react with Polymyxin B
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Topical Antibiotics
• Neomycin – Aminoglycoside
– Isolated from Streptomyces fradiae
– Inhibits protein synthesis ‐ binds 30S ribosomal subunit & may inhibit DNA polymerasey p y
– Broad spectrum activity
– Reported resistance = Plasmid mediated• Cross resistance to other AG atbx is possible
– Not absorbed through intact skin
– Can be absorbed through denuded or damaged epithelium
Neomycin cont’d
• Systemic toxicities likely if absorbed
– Irreversible ototoxicity; cilia/hair cells
– Renal clearanceRenal clearance
• Contact sensitivity
– Prevalence 1‐6%
– Incidence 3‐ 6%
– Has its own ICD‐9 code
• Cross reactivity
Topical Antibiotics
• Polymyxin B– Isolated from Bacillus polymyxa; soil organism
– Destroys bacterial membranes with surface detergent‐like interaction; increases celldetergent like interaction; increases cell permeability
– Mostly active against gram negative organisms
– Added to cocktail compound for broader use
– Little systemic absorption due to size
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Topical Antibiotics
• Mupirocin (bactroban)
– Formerly aka pseudononic acid
• major metabolite derived from Pseudomonas fluorescens
– Inhibits bacterial RNA and protein synthesis by binding to tRNA synthetasey
– Does not cross react w/ other topicals
– Broad gram positive and negative coverage
– Resistance not uncommon
– Rare systemic absorption
– Contact dermatitis reported
HOT FOOT
9/06
What to treatWhat to treat WITHWITH ????
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Core Systemic Oral Antimicrobials useful in the Outpatient Setting
• � ‐lactams
• Sulfa – based• LincosamidesLincosamides
• Macrolides
• Quinolones• Tetracyclines• Oxazolidanone
� ‐lactams
All have similar chemical core structure: �‐lactam ring