Surgical Wounds and Antimicrobial prophylaxis Dr. Philip G. Murphy Consultant in Medical Microbiology Adelaide and Meath Hospitals incorporating the National Children’s Hospital.

History 1862Pasteur 1865Lister 1866Semmelweiss 1940’sAntibiotic era Today?? Postantibiotic era <2 %

Pathogenesis Skin flora into wound margins / deep sites risk factors eg haematoma, ischaemia, prostheses Bacterial virulence eg GNB + anerobes

Definitions Spectrum from wound margin erythema through local invasion, abscess, bacteraemia

Classifiaction and Rates Clean - no intrinsic bacterial flora<2 % Clean / contaminated - involving a viscus with bacterial flora8% Contaminated - involves spillage of viscus content15% Dirty - involves inflamation or viscus perforation40%

Bacteriology UK Survey: Staphylococci40-45 % GNB40-45 % other aerobes6 % anaerobes5 % Specific surgery types have different rates:

Bacteriology Staphylococci and skin flora in bone and cardiac surgery GNB in biliary surgery Streptococci and anaerobes in gynae Colonic surgery: aerobic GNB / G Enterococci / G Bacteroides /G anaerobic cocci10 10 / G

Prevention Skin preparation: skin cleaning, disinfection, opsite Bowel preparation: No irrigation, diets, or non- absorbable antibiotics Theatre technique: workflow zoning, air flow, CSSD, restricted staffing, aseptic technique etc. Wound management Dressing, no touch technique, closed drainage

Prophylaxis - principles First dose immediately pre-op maximum of 3 doses or 24h period Rarely > 24h parenteral, PR No non-absorbables Rarely required in clean or clean/contaminated

Prophylaxis - specific IndicationAntibioticDuration above knee amputationbenzyl penicillin1 dose Cholecystectomycefuroxime1 dose Appendicectomymetronidazole3 doses ColectomyCefuroxime +3 doses metronidazole vaginal hysterectomyas above as above or augmentin Prosthetic hip replacementcefuroxime2 doses Prosthetic heart valvecefuroxime or flucloxtid <48h Vascular prosthesisas aboveas above

Treatment Topical Vs systemic Saline Vs disinfectant Vs antibiotic Target organisms Vs culture empirical Vs culture targetted one drug Vs two Remove all prostheses / implants pus collection drainage

Surveillance Infection Control Team Link nurses Databases Early discharge, day surgery Post discharge