Pathogenesis of Bacterial Vaginosis: Discussion of Current Hypotheses

Abstract

In April 2015, the Division of Microbiology and Infectious Diseases of the National Institute of Allergy and Infectious Diseases hosted an experts technical consultation on bacterial vaginosis (BV), where data regarding controversies over the pathogenesis of BV were discussed. The discussion on the epidemiology and pathogenesis of BV is presented here, and several hypotheses on its pathogenesis are critiqued. Rigorous hypothesis-driven studies are needed to ultimately determine the cause of BV. This information is vital for the prevention and control of this important infection and its adverse public health consequences.

Keywords: Gardnerella; bacterial vaginosis; vaginal flora.

Figure 1.

As depicted in the model, Gardnerella vaginalis is not part of the normal vaginal flora acquired at birth but is transmitted through sexual activity with an infected partner. It has the necessary virulence factors to adhere to host vaginal epithelium and successfully compete with normal vaginal flora for dominance. Infection with G. vaginalis results in increased pH and decreased reduction-oxidation (redox) potential, favoring increased growth of host anaerobes and suppression of lactobacilli. Reproduced with permission from Schwebke et al [48]. Abbreviations: BV, bacterial vaginosis; NH₃, ammonia.