Prophylaxis against wound infection following herniorrhaphy or breast surgery

The effect of perioperative antibiotic prophylaxis on definite wound infections was assessed for 3202 herniorrhaphies or selected breast surgery procedures. Patients were identified preoperatively and monitored for greater than or equal to 4 weeks. Thirty-four percent of patients (1077/3202) received prophylaxis at the discretion of the surgeon; 86 definite wound infections (2.7%) were identified. Prophylaxis recipients were at higher risk for infection, with a higher proportion of mastectomies, longer procedures, and other factors. Patients who received prophylaxis experienced 41% fewer definite wound infections (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.35-0.99; P = .04) and 65% fewer definite wound infections requiring parenteral antibiotic therapy (OR, 0.35; 95% CI, 0.15-0.88; P = .02) after adjustment for duration of surgery and type of procedure. Additional adjustment for age, body mass index, the presence of drains, diabetes, and exposure to corticosteroids did not change the magnitude of this effect meaningfully. The effect of prophylaxis was similar for all procedures studied. In the absence of formal guidelines, surgeons at these institutions administered prophylaxis preferentially to patients at highest risk.