[Use of cephalosporins as antibiotic prophylaxis in cesarean section].

Cefoxitin, a second-generation cephalosporin, was compared with cefazolin, a first-generation cephalosporin, and a placebo in a prospective, double-blind study of antibiotic prophylaxis in women undergoing nonelective cesarean section. In the groups that received cefazolin or the placebo there eas no statistically significant change in colonization of the cervix by aerobic bacteria by the fourth day after the operation, but there was a statistically significant increase in colonization by anaerobes. Cefoxitin had the opposite effect. Of the 14 postoperative infections in 11 patients, significantly more were in patients who had received the placebo; the numbers were too small to show a difference in effectiveness between the two antibiotics. Of the microorganisms implicated as the infectious agents, group B Streptococcus was the most frequent aerobe, and Peptostreptococcus and Bacteroides bivius were the most frequent anaerobes. Among the 15 patients for whom at least one perioperative specimen yielded positive culture results, a postoperative infection developed in 5 of the 6 who received the placebo, 2 of the 4 who received cefazolin and 1 of the 5 who received cefoxitin.