surgical wounds and antimicrobial prophylaxis dr. philip g. murphy consultant in medical...

Surgical Wounds and Antimicrobial prophylaxis

Dr. Philip G. Murphy

Consultant in Medical Microbiology

Adelaide and Meath Hospitals incorporating the National Children’s Hospital.

History

• 1862 Pasteur

• 1865 Lister

• 1866 Semmelweiss

• 1940’s Antibiotic 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 flora 8%• Contaminated - involves spillage

of viscus content 15%• Dirty - involves inflamation or

viscus perforation 40%

Bacteriology

• UK Survey:

Staphylococci 40-45 %

GNB 40-45 %

other aerobes 6 %

anaerobes 5 %

• 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 10 6-7 / G

Enterococci 10 5-6 / G

Bacteroides 10 9-11 /G

anaerobic cocci 10 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 managementDressing, 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

Indication Antibiotic Durationabove knee amputation benzyl penicillin 1 dose

Cholecystectomy cefuroxime 1 dose

Appendicectomy metronidazole 3 doses

Colectomy Cefuroxime + 3 doses

metronidazole

vaginal hysterectomy as above as above

or augmentin

Prosthetic hip replacement cefuroxime 2 doses

Prosthetic heart valve cefuroxime or fluclox tid <48h

Vascular prosthesis as above as 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