Prevotella is a genus of anaerobic bacteria that calls many parts of the human body home, including the gut, skin, oral cavity, and, importantly, the vaginal microbiome. Known for thriving in low-oxygen environments, these microbes are considered commensal—harmless companions in a healthy ecosystem. However, their behavior can shift depending on their environment and the balance of other microbes around them.

In the gut, Prevotella is typically associated with a fiber-rich diet, aiding in the digestion of complex carbohydrates. Yet, their role in the vaginal microbiome is more nuanced. With as many as 50 species identified across the body, a few, such as P. bivia, P. timonensis, and P. amnii, can inhabit the vagina under certain conditions. While their presence alone doesn't always indicate an issue, these species have the potential to influence the balance of the vaginal ecosystem, depending on the surrounding microbial community and environmental factors.

Can Prevotella Cause Vaginal Infections?

While Prevotella itself isn’t solely responsible for infections, it plays an active role in creating the conditions that allow them to occur. Under normal circumstances, Lactobacillus bacteria dominate the vaginal environment, producing lactic acid to maintain a low pH and discourage the overgrowth of harmful bacteria. But when this balance is disrupted—due to factors like antibiotics, hormonal changes, or excessive douching—Prevotella can take advantage of the situation. Prevotella often works alongside other bacteria, such as Gardnerella, to form biofilms: sticky, protective layers that attach to the vaginal lining, creating an environment where bacteria can thrive and evade the body’s natural defenses.

What makes Prevotella particularly concerning is its ability to produce enzymes like sialidase, which break down the vaginal mucosa. This protective barrier is the first line of defense against harmful microbes. Once weakened, the vaginal lining becomes more vulnerable, and Prevotella can pave the way for other bacteria to join in, resulting in a cascade of microbial imbalance.

Can Prevotella Cause BV?

Prevotella species, particularly P. bivia, play a supportive role in the development of BV. These bacteria often work in tandem with Gardnerella, which are present in up to 95% of BV cases, contributing to a cascade of changes in the vaginal environment. Their collaboration includes the formation of biofilms and the production of enzymes and byproducts that disrupt the normal balance of protective bacteria like Lactobacillus.

While Prevotella doesn’t act as the sole cause of BV, its role in this microbial imbalance is significant. By altering the vaginal ecosystem, Prevotella helps create conditions that allow BV to take hold and persist.

Does Prevotella Cause Odor and Discharge?

One of the most noticeable signs of bacterial vaginosis (BV) is a distinct, fishy odor, and Prevotella is one of the key bacteria involved. This odor is caused by compounds called biogenic amines, which are produced when certain bacteria break down nutrients in the vaginal environment. Among these amines, putrescine and cadaverine are particularly responsible for the unpleasant smell often compared to fish.

Prevotella is part of a group of bacteria, including Dialister, Parvimonas, Megasphaera, Peptostreptococcus, and Veillonella, that have the genetic ability to produce these odor-causing compounds. While the exact mechanisms are still being studied, their role in BV highlights how shifts in the vaginal microbiome can lead to noticeable and uncomfortable symptoms.

These changes often accompany increased discharge and alterations in vaginal pH, further signaling a disruption in the microbiome's balance.

How to Treat Prevotella

To address Prevotella overgrowth, your healthcare provider will likely prescribe an antibiotic as the first line of treatment. Common options include metronidazole or clindamycin, which work to reduce bacterial overgrowth and ease symptoms. However, those sticky biofilms we talked about—the protective layers bacteria like Prevotella and Gardnerella form—make it difficult for antibiotics to fully eliminate them. This is one reason more than half of women with bacterial vaginosis (BV) experience a recurrence within six months, even after completing treatment.

Breaking the cycle involves restoring healthy bacteria. Encouraging the growth of Lactobacillus, the beneficial bacteria in your vaginal microbiome, is a key step. These protective microbes establish a favorable environment that inhibits the proliferation of Prevotella and other pathogenic bacteria, promoting a stable and healthy microbiome.

To support this process, incorporate microbiome-friendly products into your routine:

Vaginal suppositories: These introduce healthy bacterial strains like Lactobacillus, helping to restore balance to the microbiome and prevent harmful bacteria from thriving.

pH-balanced vaginal moisturizers: These hydrate and soothe sensitive tissues, creating an environment that supports healthy bacteria and overall vaginal health.

It’s equally important to avoid products with harsh ingredients like parabens, petrochemicals, or synthetic fragrances, as these can further disrupt the delicate balance of your microbiome.

FAQ

How is Prevotella treated if it contributes to BV?

Treatment typically starts with antibiotics like metronidazole or clindamycin to reduce bacterial overgrowth. However, restoring healthy bacteria, such as Lactobacillus, is key to maintaining balance and reducing the risk of recurrence.

Is Prevotella good bacteria or harmful bacteria?

It depends on the location and balance of the microbiome. In the gut, Prevotella can play a beneficial role in digesting complex carbohydrates. However, in the vaginal microbiome, an overgrowth of Prevotella can disrupt the natural balance and contribute to bacterial vaginosis (BV) when present in excessive amounts.