What is the treatment for bacterial vaginosis?

Vaginal Infection Has Been Long Linked To Pregnancy Risks — And Doctors Finally Know Why

Symptoms of bacterial vaginosis include vaginal discharge or pain in the area. HENADZY – stock.Adobe.Com

The researchers say further exploration of the surface of vaginal epithelial cells could make diagnosing BV easier.

"We now have a blueprint of the glycans present on epithelial cells in the vagina, and we showed that these glycans are shaped by the bacteria that live there," said Warren G. Lewis, a UCSD assistant professor.

"However, it will take more work to fully understand the functions of glycans in the vaginal epithelium and how bacterial vaginosis impacts those functions."

In the meantime, they recommend

avoiding douching or using scented products, which could disrupt the vagina's delicate balance of bacteria.

BV typically occurs in women who are sexually active — it's often treated with antibiotics.

Symptoms include vaginal discharge and pain.

Lewis noted that "even when bacterial vaginosis is identified and treated with antibiotics, recurrences occur in most individuals within a year."

Not seeking treatment can lead to pre-term birth for pregnant women or

sexually transmitted diseases like chlamydia and gonorrhea.

Microbiome Study May Have Finally Solved An Enduring Mystery In Gynecology

Let's not beat around the bush: if you've got a vagina, it's teeming with bacteria. That's usually a good thing. The thousands of microorganisms colonizing every vaginal nook and cranny are there to keep it healthy, maintain a low pH (hovering anywhere between 3.8 and 5), and serve as the defensive line against invading infections.

But when the delicate microscopic balance is disrupted, serious harm can ensue. For around 30 percent of reproductive-aged women worldwide, these disruptions led to a condition called bacterial vaginosis, where there's an overgrowth of some "bad" bacteria over other "beneficial" ones. Bacterial vaginosis doubles one's risk of acquiring sexually transmitted infections like HIV and for pregnant individuals, it can increase the risk of pre-term birth and even pregnancy loss. Some recent studies suggest bacterial vaginosis may even increase your risk for cervical cancer.

It's not clear why this disastrous bacterial overgrowth happens or even how it damages vaginal health. One piece of the puzzle, according to a new study published Wednesday in the journal Science Translational Medicine, may have to do with bundles of sugar molecules attached to the outside of cells comprising the vagina, called epithelial cells.

Researchers led by the University of California, San Diego, found that bacteria associated with bacterial vaginosis, like Gardnerella, produce enzymes that eat away at these sugar molecules. Because these sugars act as a protective barrier, their destruction may expose the vagina to attack by other intrusive bacteria and viruses, encourage inflammation, and thereby undermine reproductive health.

"The fact that we were able to replicate some of the effects of bacterial vaginosis suggests that we may be on the right track to finding a common cellular origin for the various complications associated with this condition," Amanda Lewis, a professor in obstetrics, gynecology, and reproductive sciences at UC San Diego School of Medicine who co-authored the study, said in a press release.

Eating the protective layer

The fact bacterial vaginosis may be connected to bacteria munching down on sugar molecules protecting vaginal epithelial cells, called glycans, has been suggested in previous studies as far back as the 1990s. Bacterial enzymes, which help break down other molecules, were thought to be involved, as other studies have found with other types of sugars associated with vaginal and cervical epithelial cells. However, scientists weren't quite sure what enzymes targeting glycans were doing.

For their study, Lewis and her colleagues looked at epithelial cells taken from vaginal fluid samples collected by the Contraceptive CHOICE Project, a separate study established in 2007 by the Washington University School of Medicine in St. Louis to provide nearly 10,000 St. Louis, Missouri, residents with birth control without any financial barriers.

Comparing samples from individuals with and without bacterial vaginosis, the researchers found the shield of sugar molecules encircling vaginal epithelial cells, called the glycocalyx, wasn't as thick in the bacterial vaginosis samples compared to the normal ones. Instead, there were tattered remnants of broken-down glycans clinging to cells.

But what was behind the damage? The culprit appeared to be sialidase, an enzyme produced by the bad bacteria associated with bacterial vaginosis. When the researchers exposed normal vaginal epithelial cells to sialidase from bacteria like Gardnerella — often one of the most abundant microbes found in bacterial vaginosis — these cells also had their glycans gobbled right up.

More research needed

By losing their protective glycan layer, bacterial vaginosis appears to put vaginal epithelial cells in a vulnerable position that makes them easier to target and stick to by harmful bacteria. The researchers say the tie-in to reproductive health may be through processes like inflammation and cell death. But sussing this out even further to connect the dots to sexually transmitted disease risk or pre-term birth will be an ongoing study.

However, more immediately, these findings may help diagnose bacterial vaginosis more easily, especially as many individuals may have the condition and be unaware, not to mention run the risk of getting it again months later, even with antibiotic treatment.

"We now have a blueprint of the glycans present on epithelial cells in the vagina, and we showed that these glycans are shaped by the bacteria that live there," Warren Lewis, an assistant professor in obstetrics, gynecology, and reproductive sciences at UC San Diego School of Medicine who also co-authored the study, said in the press release. "However, it will take more work to fully understand the functions of glycans in the vaginal epithelium and how bacterial vaginosis impacts those functions."

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Study Unravels How Bacterial Vaginosis Disrupts Vaginal Health

Bacterial vaginosis is a common condition in which the natural microbiome of the vagina falls out of balance, sometimes leading to complications in sexual and reproductive health. But exactly how these bacterial populations disrupt vaginal health has remained unclear.

Researchers at University of California San Diego School of Medicine have now found that in bacterial vaginosis, certain bacterial species dismantle protective molecules on the surface of the cells lining the vagina, dysregulating key processes that mediate cell turnover, death and response to surrounding bacteria.

The findings, published November 29, 2023 in Science Translational Medicine, may help explain why bacterial vaginosis is associated with many adverse sexual and reproductive health outcomes -; a longstanding mystery in gynecology.

The balance of bacteria in the vagina play a key role in a person's health. Bacterial vaginosis is known to be linked to pregnancy loss, preterm birth, postsurgical infections, pelvic inflammatory disease and sexually transmitted infections."

Warren G. Lewis, PhD, co-corresponding author, assistant professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at UC San Diego School of Medicine

Bacterial vaginosis is one of the most common vaginal conditions among women of reproductive age. The CDC estimates that in the United States, bacterial vaginosis affects approximately 29% of women between the ages of 14 and 49. While the condition is associated with higher risks of many health complications, it does not always cause noticeable symptoms on its own.

"Even when bacterial vaginosis is identified and treated with antibiotics, recurrences occur in most individuals within a year," said Lewis.

To understand how these bacteria impact vaginal health, the researchers studied the epithelial cells that line the vagina. Because the surface of epithelial cells comes into contact with bacteria and other microbes, it is densely coated with sugar chains, called glycans. Glycans play key roles in cell biology and disease, such as protecting against microbial invasion and helping cells adhere to each other. However, glycans can also be a food source for bacteria.

"We knew that bacterial species implicated in bacterial vaginosis can feed on glycans in secreted mucus. The current study allowed us to look directly at what those bacteria are then doing to the vaginal epithelial surface landscape on a biochemical and microscopic level," said co-corresponding author Amanda Lewis, PhD, professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at UC San Diego School of Medicine.

The researchers obtained epithelial cells derived from human vaginal specimens and used them to explore glycan dynamics. With a combination of biochemistry and microscopy techniques, they discovered that in bacterial vaginosis, bacteria release enzymes called sialidases that partially dismantle protective glycan molecules on the surface of epithelial cells. The researchers were also able to induce a bacterial-vaginosis-like state in 'normal' epithelial cells by treating them directly with sialidase enzymes produced in the laboratory.

"The fact that we were able to replicate some of the effects of bacterial vaginosis suggests that we may be on the right track to finding a common cellular origin for the various complications associated with this condition," said Amanda Lewis.

Studying the surface of vaginal epithelial cells at this level of biochemical detail could help make diagnosing bacterial vaginosis easier. The authors suggest differences in glycosylation patterns could also help identify subsets of people with the condition who may be at the greatest risk for negative health outcomes, including recurrence.

"We now have a blueprint of the glycans present on epithelial cells in the vagina, and we showed that these glycans are shaped by the bacteria that live there," said Warren Lewis. "However, it will take more work to fully understand the functions of glycans in the vaginal epithelium and how bacterial vaginosis impacts those functions."

As research on the mechanisms of bacterial vaginosis continue, clinicians urge people with vaginas to familiarize themselves with the symptoms of bacterial vaginosis and avoid douching or using scented products, which could result in further microbial imbalances.

Co-authors include: Kavita Agarwal, Biswa Choudhury, Sydney R. Morrill, Daisy Chilin-Fuentes, Sara B. Rosenthal, Kathleen M. Fisch at UC San Diego, Lloyd S. Robinson at University of Washington School of Medicine, Yasmine Bouchibiti and Carlito B. Lebrilla at University of California Davis, Jenifer E. Allsworth at the University of Missouri, and Jeffrey F. Peipert at Indiana University School of Medicine.

This study was funded, in part, by the National Institutes of Health (grants R01 AI114635, R01 AI127554 and UL1TR001442), the Burrroughs Wellcome Fund Preterm Birth Initiative and the University of California through the UC Glycosciences Consortium for Women's Health.

Source:

Journal reference:

Agarwal, K., et al. (2023) Resident microbes shape the vaginal epithelial glycan landscape. Science Translational Medicine. Doi.Org/10.1126/scitranslmed.Abp9599.

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