Bacterial Vaginosis: Vaginal Microbes’ Attack Linked to Serious Health Outcomes

Bacterial vaginosis, like many women’s health conditions, has a serious but underappreciated impact. In vaginosis, the vagina’s natural microbiome – the community of microorganisms that call it home – becomes disrupted. The condition affects nearly a third of women aged 14–49.  But it remained poorly understood – until now.

Disease links

“Bacterial vaginosis is known to be linked to pregnancy loss, preterm birth, postsurgical infections, pelvic inflammatory disease and sexually transmitted infections,” says Dr. Warren G. Lewis, an Assistant Professor at the University of California, San Diego.

The majority of people with vaginosis who are treated with antibiotics show recurrence of the condition within a year. The use of douches or scented products can further disrupt the vaginal microbiome.

Despite these links to other diseases, bacterial vaginosis is often asymptomatic, meaning tools for diagnosis of the conditions are needed.

Cell breakdown

Lewis is a co-author on a new paper that shows that vaginosis can lead to the breakdown of a layer of protective molecules that lines the vagina. These changes can affect healthy processes like cell turnover and antibacterial responses.

Lewis’s paper focuses on glycans, a class of specialized carbohydrates. Glycan chains are found on all cell surfaces. In addition to their important roles in healthy cell function, glycans can also be food sources for bacteria. In the vagina, epithelial cells sit in direct contact with microbial bacteria.

Lewis and colleagues extracted epithelial cells from volunteers’ vaginas and used them to test changes that could induce vaginosis. “We show that certain bacterial species make glycan-degrading enzymes,” says Lewis. These enzymes change the physical properties of these normally protective cells. The enzymes could even cause vaginosis-like changes in healthy epithelial cells. The authors hope that these findings could help identify a linked cellular origin for vaginosis and the more severe complications it is associated with.

Diagnostic advances

The biggest advance proposed by the current study could be the development of diagnostics that would highlight people at risk of vaginosis-related negative health outcomes and reoccurrence. Lewis says that more research will be required to fully map the interaction between cell and microorganism at the vaginal frontier. “Before we can truly battle the negative impact of BV, we need to understand how individual bacteria and the community of bacteria in BV contribute to the harmful effects we associate with BV,” he concluded.

Reference: Agarwal K, Choudhury B, Robinson LS, et al. Resident microbes shape the vaginal epithelial glycan landscape. Sci Trans Med. 2023;15(724):eabp9599. doi:10.1126/scitranslmed.abp9599