May 08, 2013
1 min read

Research unlocking clues to bacterial vaginosis

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Dozens of bacterial species have been linked to bacterial vaginosis, leading to debates in the scientific community over which bacteria actually cause the condition and its complications. New research provides evidence that mucus layers and cells lining the surface of the vagina are damaged in women with bacterial vaginosis and shows that a single organism, Gardnerella vaginalis, is an important contributor to this damage.

"Bacterial vaginosis is a mysterious condition in which healthy bacteria disappear and an unhealthy mixture of bacteria overgrow in the vagina," study researcher Amanda L. Lewis, PhD, of the University of Washington, told Infectious Disease News. "The condition is extremely common, occurring in approximately one in three women, and has been linked with serious pregnancy complications and higher risks of acquiring sexually transmitted infections. However, little is known about what causes bacterial vaginosis or why it is associated with reproductive complications."

Amanda L. Lewis, PhD 

Amanda L. Lewis

G. vaginalis is commonly found in the vaginal fluids of women with bacterial vaginosis and in some women who do not have the condition, but results of mouse studies have shown than G. vaginalis causes increased shedding of the outermost cells covering the vaginal lining.

Based on their observations in mice, Lewis and colleagues compared vaginal samples from women with and without bacterial vaginosis and found that the outermost cells from the lining of the vagina are shed in higher numbers during bacterial vaginosis.

Using biochemical approaches, the researchers demonstrated that G. vaginalis uses an enzyme called sialidase to detach sialic acids, an important part of the mucus that covers and protects the vaginal lining. When the researchers tested vaginal mucus samples from women with bacterial vaginosis, they found lower levels of sialic acids than in women who did not have the condition.

“Our analyses of clinical specimens from women with [bacterial vaginosis] revealed a measureable epithelial exfoliation response compared to women with normal flora, a phenotype that, to our knowledge, is measured here for the first time,” the researchers concluded. “The results of this study demonstrate that G. vaginalis is sufficient to cause [bacterial vaginosis] phenotypes and suggest that this organism may contribute to [bacterial vaginosis] etiology and associated complications.”

Disclosure: Lewis reports no relevant financial disclosures.