Bacterial flora of patients with prematurely ruptured membranes.

Twenty consecutive patients with premature rupture of the membranes were studied to determine the vaginal, endocervical, and neonatal bacteriologic flora. Patients who had membranes ruptured for more than 12 hours had more anaerobic species isolated from vaginal plus endocervical or endocervical cultures alone than did those patients with membranes ruptured for less than 12 hours. Overall, aerobic organisms were more frequently isolated than anaerobic organisms, but the majority of cultures were of a mixed flora. Streptococci, corynebacteria, and Bacteroides organisms were the most frequently isolated organisms from all sites cultured. Lactobacilli were isolated in only 45% of endocervical and vaginal cultures, and Enterobacteriaceae were infrequently encountered. This study indicates that there is a change toward a preponderance of anaerobic species in the birth canal when membranes are ruptured for more than 12 hours, and that this change is detectable before delivery.