Vaginal colonization with resistant aerobic bacteria after antibiotic therapy for endometritis

To assess the effect of broad-spectrum antibiotic therapy upon vaginal colonization, we collected vaginal specimens for culturing at the end of therapy from 50 patients treated for postcesarean section endometritis. Infected patients had participated in a double-blind therapy protocol and had received either clindamycin plus gentamicin or cefamandole plus placebo. Repeat vaginal culturing was performed 6 weeks later. Similar vaginal specimens for culturing were collected from 25 control patients who also had undergone cesarean section but had not received antibiotics. Of 26 patients treated with cefamandole, 16 (62%) developed vaginal colonization with isolates resistant to that drug; of 24 patients treated with clindamycin-gentamicin, two (8%) developed isolates resistant to these agents (p less than 0.001). Among 25 control patients, there was only one isolate resistant to cefamandole and none resistant to clindamycin-gentamicin. Compared to controls, more antibiotic-treated patients developed isolates resistant to cefamandole (p = 0.001) and to clindamycin-gentamicin (p = 0.06). Colonization did not persist, and there were no late infections in this population.