Vaginal microbial flora: practical and theoretic relevance.

The bacterial flora of the female reproductive tract is a focal point for the study of infectious disease in obstetrics and gynecology, as it is recognized that many pelvic infections involve bacteria resident on the cervical-vaginal epithelium. The vaginal flora contains a large variety of bacterial species, including aerobic and anaerobic organisms, as revealed by modern microbiologic methods. Recent studies have indicated that certain organisms commonly involved in pelvic infections, particularly those following genital tract surgery, name Escherichia coli and Bacteroides fragilis, appear to be underrepresented in relationship to the infectious complications they cause. A possible explanation of this phenomenon has been suggested based on the finding that traumatic events in the reproductive tract, including parturition, surgery, and invasive malignancy, result in increased colonization by organisms commonly involved in pelvic infections. Other changes in the flora related to the host's hormonal milieu were identified and are generally less profound than those related to trauma. We have reviewed some of the newer aspects of our understanding of the genital flora, such as quantitation of the vaginal flora, which should continue to improve our understanding of the role of the genital flora in disease states.