On antibiotic prophylaxis in cardiac surgery: a risk factor for wound infection.

During a 30-month period, median sternotomy wound infections or endocarditis developed during the first 60 days postoperatively following 20 of 1,204 (1.7%) adult cardiac procedures at the University of Maryland Hospital. Fifty percent of the infected patients received perioperative clindamycin prophylaxis. A retrospective study was conducted in which the odds ratio estimate of the relative risk of sternotomy infection or endocarditis for patients receiving clindamycin prophylaxis compared with patients receiving cefamandole was found to be 17.0 (p less than .001) using population controls and 8.25 (p less than .001) using matched controls. Seventy-five percent of the organisms causing infections, principally Staphylococcus epidermidis, were resistant in vitro to clindamycin. Perioperative clindamycin administration was not fully effective in preventing wound infection following cardiac surgery at our hospital, thus providing indirect evidence for the efficacy of prophylaxis with cephalosporin-containing regimens. Trials of alternative antibiotics to clindamycin for prophylaxis in penicillin-allergic patients undergoing cardiac surgery are indicated.