Bacteria may contribute to premature births, STDs

April 23, 2013, Washington University School of Medicine
Bacteria may contribute to premature births, STDs
Gardnerella vaginalis, a common species of bacteria, may be an important contributor to bacterial vaginosis, a condition linked to preterm birth and increased risk of sexually transmitted diseases. Credit: Wandy Beatty

(Medical Xpress)—New research at Washington University School of Medicine in St. Louis points to a common species of bacteria as an important contributor to bacterial vaginosis, a condition linked to preterm birth and increased risk of sexually transmitted diseases.

The condition affects one in every three , making it more common than . But often does not cause significant symptoms, leaving many women unaware they have it.

"Bacterial vaginosis can significant health problems, but it is not a common topic of conversation between patients and their ," says Amanda Lewis, PhD, assistant professor of . "Our findings, which come from new of the condition, may be a first step toward a better understanding of how to treat bacterial vaginosis and prevent serious complications linked with the condition."

Bacterial vaginosis occurs when the typical mix of microbes in the vagina is knocked off-kilter. In some cases, bacterial vaginosis causes a change in the consistency of vaginal fluids and an unpleasant odor. The condition is diagnosed through examination of the vagina and tests of the vaginal fluids. Doctors typically treat it with antibiotics, but the condition often recurs.

Lewis and her colleagues recently published back-to-back papers on bacterial vaginosis, the first in Journal of Biological Chemistry and the second in PLOS One.

Dozens of have been linked with bacterial vaginosis, leading to heated debates in the scientific community over which bacteria actually cause the condition and its complications. The new research provides evidence that mucus layers and cells lining the surface of the vagina are damaged in women with bacterial vaginosis and suggests that a single organism, Gardnerella vaginalis, is likely the cause.

G. vaginalis is commonly found in the vaginal fluids of women with bacterial vaginosis and in some women who don't have the condition. The latter had led many researchers to dismiss the bacterium's potential contributions to bacterial vaginosis.

Working in mice to simulate this condition, Nicole Gilbert, PhD, postdoctoral fellow, showed that G. vaginalis causes increased shedding of the outermost cells covering the vaginal lining.

"We think the vaginal lining is shed as part of the body's effort to eliminate bacteria," says Gilbert. "However, this shedding may also expose sensitive underlying tissues. This may be important for understanding why women with bacterial vaginosis are more susceptible to sexually transmitted diseases and urinary tract infections."

Based on their observations in mice, the researchers 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.

"This is the first time, to our knowledge, that the presence of increased numbers of shed cells has been detected in bacterial vaginosis in humans," Lewis says. "These results also suggest that G. vaginalis is the cause of this increase."

The researchers examined the ability of G. vaginalis to degrade mucus, which normally helps protect the vagina and uterus from infection.

Using biochemical approaches, Warren Lewis, PhD, research instructor in medicine, and Lloyd Robinson, PhD, research technician, showed that the bacterium uses an enzyme called sialidase to detach sialic acids, which are an abundant and important part of mucus.

The research team showed that the bacterium not only breaks up mucus barriers but also makes a meal of some of the components it frees from the barriers.

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. Mice also had lower levels of vaginal sialic acids after infection with G. vaginalis.

"This is the first time that a bacterium associated with vaginosis has been shown to participate in mucus degradation," says Lewis. "This is significant because infection of the uterus is a common cause of preterm birth and likely requires degradation of the mucus plug, a physical structure that protects the pregnant uterus from bacteria in the vagina."

Explore further: Bacterial vaginosis is associated with higher risk of female-to-male transmission of HIV

More information: Lewis WG, Robinson LS, Gilbert NM, Perry JC, Lewis AL. Degradation, foraging and depletion of mucus sialoglycans by the vagina-adapted actinobacterium Gardnerella vaginalis. Journal of Biological Chemistry, published online.

Gilbert NM, Lewis WG, Lewis AL. Clinical features of bacterial vaginosis in a murine model of vaginal infection with Gardnerella vaginalis. PLOS One, published online.

Related Stories

Bacterial vaginosis is associated with higher risk of female-to-male transmission of HIV

June 26, 2012
An investigation led by UCSF has found that the risk of female-to-male HIV transmission is increased three fold for women with bacterial vaginosis, a common disorder in which the normal balance of bacteria in the vagina is ...

New research discoveries shed light on common STI

April 2, 2013
Research led by David H. Martin, MD, Professor and Chief of Infectious Diseases at LSU Health Sciences Center New Orleans, has found that a common sexually transmitted infection-causing parasite "cultivates" bacteria beneficial ...

Petroleum jelly tied to vaginal infection risk in study

March 8, 2013
(HealthDay)—Women who use petroleum jelly vaginally may put themselves at risk of a common infection called bacterial vaginosis, a small study suggests.

Recommended for you

Researchers illustrate how muscle growth inhibitor is activated, could aid in treating ALS

January 19, 2018
Researchers at the University of Cincinnati (UC) College of Medicine are part of an international team that has identified how the inactive or latent form of GDF8, a signaling protein also known as myostatin responsible for ...

Bioengineered soft microfibers improve T-cell production

January 18, 2018
T cells play a key role in the body's immune response against pathogens. As a new class of therapeutic approaches, T cells are being harnessed to fight cancer, promising more precise, longer-lasting mitigation than traditional, ...

Weight flux alters molecular profile, study finds

January 17, 2018
The human body undergoes dramatic changes during even short periods of weight gain and loss, according to a study led by researchers at the Stanford University School of Medicine.

Secrets of longevity protein revealed in new study

January 17, 2018
Named after the Greek goddess who spun the thread of life, Klotho proteins play an important role in the regulation of longevity and metabolism. In a recent Yale-led study, researchers revealed the three-dimensional structure ...

The HLF gene protects blood stem cells by maintaining them in a resting state

January 17, 2018
The HLF gene is necessary for maintaining blood stem cells in a resting state, which is crucial for ensuring normal blood production. This has been shown by a new research study from Lund University in Sweden published in ...

Magnetically applied MicroRNAs could one day help relieve constipation

January 17, 2018
Constipation is an underestimated and debilitating medical issue related to the opioid epidemic. As a growing concern, researchers look to new tools to help patients with this side effect of opioid use and aging.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.