Are first-generation cephalosporins effective for antibiotic prophylaxis in elective surgery of the colon?

First-generation cephalosporins have recently declined in popularity as antibiotics for prophylaxis in elective surgery of the colon, but their efficacy has not been defined precisely. In a prospective randomized study, 44 patients who underwent elective colonic operations received, preoperatively, cefazolin in a parenteral dose adequate to kill aerobic coliforms. Six had wound infections; Bacteroides fragilis was grown, along with other organisms, from all these wounds. In contrast, only 1 of 57 similar patients had a wound infection after receiving, preoperatively, erythromycin base and metronidazole orally--directed at anaerobic bacteria. Local contamination, predominantly by anaerobic bacteria, is the main cause of wound infection after elective surgery of the colon. Even in what seems to be adequate dosage, first-generation cephalosporins are not antibiotics of first choice for preventing wound infections after these operations.