Selective effect of cefoxitin prophylaxis on post-cesarean-section microbial flora.

A double-blind study was done to test the efficacy of cefoxitin in the prevention of post-cesarean-section infection. The antibiotic was given in three 2-g doses; the initial dose was given immediately after the cord was clamped, and subsequent doses were given four and eight hours later. Cefoxitin prophylaxis significantly reduced morbidity serious enough to require therapeutic antibiotics or to prolong the hospital stay and led to an overall reduction in the anaerobic microbial flora of the endocervix. However, the antibiotic was selective for the overgrowth of enterococci, which were present in nearly half the postoperative cultures of patients who had received the drug. Enterococcal sepsis occurred in one patient, and three other patients had significant bacteriuria and/or urinary tract infections from enterococci. No cefoxitin-resistant strains of Enterobacteriaceae, among species normally sensitive to the drug, were isolated from the stool samples after prophylaxis. The risk of enterococcal colonization and superinfection must be weighted against the benefits of reduction of the infection risk when deciding upon routine antibiotic prophylaxis for cesarean section.