Prophylactic use of antibiotics in surgery

Survey of complications and antimicrobial use in equine patients at veterinary teaching hospitals that underwent surgery because of colic

OBJECTIVE

To determine current practices regarding use of antimicrobials in equine patients undergoing surgery because of colic at veterinary teaching hospitals.

DESIGN

Survey.

SAMPLE POPULATION

Diplomates of the American College of Veterinary Surgeons performing equine surgery at veterinary teaching hospitals in the United States.

PROCEDURE

A Web-based questionnaire was developed, and 85 surgeons were asked to participate. The first part of the survey requested demographic information and information about total number of colic surgeries performed at the hospital, number of colic surgeries performed by the respondent, and whether the hospital had written guidelines for antimicrobial drug use. The second part pertained to nosocomial infections. The third part provided several case scenarios and asked respondents whether they would use antimicrobial drugs in these instances.

RESULTS

Thirty-four (40%) surgeons responded to the questionnaire. Respondents indicated that most equine patients undergoing surgery because of colic at veterinary teaching hospitals in the United States received antimicrobial drugs. Drugs that were used were similar for the various hospitals that were represented, and for the most part, the drugs that were used were fairly uniform irrespective of the type of colic, whereas the duration of treatment varied with the type of colic and the surgical findings. The combination of potassium penicillin and gentamicin was the most commonly used treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of this study document the implementation of recommendations by several authors in veterinary texts that antimicrobial drugs be administered perioperatively in equine patients with colic that are undergoing surgery. However, the need for long-term antimicrobial drug treatment in equine patients with colic is unknown.

Monitoring of antimicrobial prophylaxis in general surgery

The incidence of infections in general surgery is related to different factors. Cost-benefit analysis of antimicrobic prophylaxis is positive, even though incorrect use may be even dangerous (development of resistance and/or superinfections, for instance). The authors report data on a study concerning a total of 316 patients divided into two series, who had antimicrobic prophylaxis before a surgical operation. 274 patients out of 316 (or 86.7%) had an ultra-short (one-shot-only) or short (<24 hours) prophylaxis, 42 (13.3%) standard (>24 hours). The operations performed were classified following class of contamination, i.e. I (clean), II (potentially contaminated), III (contaminated). Antibiotics used were ceftizoxime, cefepime, ceftriaxone, piperacillin and gentamicin in combination. A total of 16 postoperative infections was observed (5%); 11 of these 16 belonged to class III operations. Escherichia coli and Staphylococcus aureus were isolated in most of the infected wounds. The data confirm what is reported in the literature. The authors conclude that a preoperative single-shot 3rd or 4th generation cephalosporin reduces the incidence of wound infections in clean and clean-contaminated surgery.

Scalpel blade contamination with skin bacteria during orthopedic and neurosurgical procedures in dogs

Skin incision and internal incision scalpel blades used during 40 clean canine orthopedic or neurologic operations were cultured. A biopsy of skin was taken from the incision edge and cultured aerobically and anaerobically. Culture of five skin blades, eight skin biopsies, and nine deep dissection blades resulted in bacterial growth. Results indicate that the skin blade does not add significantly to bacterial inoculum contaminating clean wounds.

Bacteriological assessment of patients undergoing major head and neck surgery

The use of chemoprophylaxis in major Head and Neck surgery is controversial. Prior to conducting a prospective trial a controlled microbiological monitoring of 32 patients was performed to determine a suitable antibiotic for prophylaxis. Wound infection occurred in 22 (68%) patients with fistulae occurring in 10 of these patients (45.5%). Pre-operative cultures were of limited value in predicting subsequent sepsis. Gram-negative aerobic bacilli were the commonest group of pathogens (34.4%) isolated post-operatively. From projected resistance profiles of pathogenic and opportunistic bacteria amoxycillin and clavulanic acid (Augmentin, Beecham Pharmaceuticals) was chosen as a suitable antibiotic.