Human gut microbiome picture showing a variety of microbes including fungi such as Candida albicans
Credit: Larry Washburn / Getty Images

Researchers at the University of California (UC) San Diego School of Medicine have made significant discoveries in understanding the complex relationship between bacterial vaginosis and adverse sexual and reproductive health outcomes.

Bacterial vaginosis, a common condition affecting nearly 29 percent of women between the ages of 14 and 49 in the United States, has long been associated with pregnancy loss, preterm birth, postsurgical infections, pelvic inflammatory disease, and sexually transmitted infections. Reporting in Science Translational Medicine, researchers are now shedding light on the mechanisms by which certain bacterial species disrupt the delicate balance of the vaginal microbiome, leading to these severe health complications.

“Bacterial vaginosis is known to be linked to pregnancy loss, preterm birth, postsurgical infections, pelvic inflammatory disease, and sexually transmitted infections,” emphasized Warren G. Lewis, an assistant professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at UC San Diego School of Medicine. The study not only highlights the severity of the conditions associated with bacterial vaginosis but also provides a deeper understanding of its underlying molecular mechanisms.

The researchers analyzed epithelial cells that line the vagina as crucial players in the interaction between bacteria and the human body. These cells are densely coated with sugar chains known as glycans, which play pivotal roles in cell biology and disease. The team discovered that in bacterial vaginosis, specific bacteria release enzymes called sialidases, which partially dismantle protective glycan molecules on the surface of epithelial cells. Remarkably, they were able to induce a bacterial-vaginosis-like state in ‘normal’ epithelial cells by treating them directly with sialidase enzymes produced in the laboratory.

Amanda Lewis, a professor in the Department of Obstetrics, Gynecology & Reproductive Sciences, said, “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.” According to the researchers, this breakthrough opens the door to potential diagnostic advancements, as studying the surface of vaginal epithelial cells at such a detailed biochemical level could aid in identifying subsets of individuals at the greatest risk for negative health outcomes, including recurrence.

While the study provides a blueprint of the glycans present on vaginal epithelial cells, Warren Lewis acknowledges that further research is needed to fully comprehend the functions of glycans in the vaginal epithelium and how bacterial vaginosis impacts these functions. As this research progresses, clinicians are urging individuals with vaginas to be vigilant about the symptoms of bacterial vaginosis and to refrain from practices such as douching or using scented products, which may exacerbate microbial imbalances.

In unraveling the complexities of the vaginal microbiome, this research not only contributes to our understanding of bacterial vaginosis but also holds the promise of more effective diagnostics and targeted interventions for individuals at risk. The authors believe that the implications of this study reach beyond gynecology, touching on broader aspects of reproductive health and paving the way for innovative approaches to tackle related complications.

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