What is the pathophysiology of bacterial vaginosis (BV)?

Updated: Oct 25, 2018
  • Author: Philippe H Girerd, MD; Chief Editor: Michel E Rivlin, MD  more...
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In BV, the vaginal flora becomes altered through known and unknown mechanisms, causing an increase in the local pH. This may result from a reduction in the hydrogen peroxide–producing lactobacilli. Lactobacilli are large rod-shaped organisms that help maintain the acidic pH of healthy vaginas and inhibit other anaerobic microorganisms through elaboration of hydrogen peroxide. Normally, lactobacilli are found in high concentrations in the healthy vagina. In BV, the lactobacilli population is reduced greatly, while populations of various anaerobes and G vaginalis are increased.

G vaginalis forms a biofilm in the vagina. [5] Some studies show that this biofilm may be resistant to some forms of medical treatment. This predominant G vaginalis biofilm has been shown to survive in hydrogen peroxide (H2 O2), lactic acid, and high levels of antibiotics. When the biofilm was subjected in the laboratory to enzymatic dissolution, susceptibility to H2 O2 and lactic acid were restored. [5] These findings may lead to future development of novel therapies involving enzymatic degradation of biofilms. No such products are currently on the market.

In a study published by Fredricks et al, G vaginalis was detected by PCR in 96% of subjects with BV and 70% of those without BV. Multiple other bacterial species were found by PCR in this study. Fredricks' study confirms the polymicrobial nature of BV and the presence of G vaginalis as one of the causative agents. [6]

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