Vaginal Biofilm: Is It the Cause of Recurring BV or Yeast Infections?

If you’ve ever had recurrent bacterial vaginosis (BV) or yeast infections, you’ve likely experienced the frustration that comes with trying to figure out why your symptoms keep coming back. Is it your diet? The soap you’re using? The sex you’re having? 

Another very likely scenario is that a biofilm has formed in your vaginal microbiome. A biofilm is a film-like structure that serves as a shield for bacteria, offering them protection from their environment and any external threat to their survival — such as the lactic acid produced by protective Lactobacilli or treatments like antibiotics and antifungals. 

Below, break down the existing research on vaginal biofilm, how it’s related to vaginal infections like bacterial vaginosis and yeast infections, and what you can do to get rid of them.

What is a biofilm?

At its simplest, a biofilm is a community of microorganisms living together in a self-made 3D structure. This structure — made of an extracellular polymeric substance (or EPS) — protects the bacteria living inside and is really good at sticking to surfaces (like your vagina’s epithelial wall).

Biofilms are usually produced by a specific bacteria or fungi, which is why they occur so frequently in the vaginal microbiome.

What does biofilm look like?

A biofilm is often microscopic, consisting of only a few bacteria. But it can be so large that it’s visible to the human eye. Some examples of biofilms you can see include the slimy surface of a rock that you pick up from the bottom of a lake, the layer of grime that builds up on your kitchen sink drain, or a layer of plaque between your teeth that you remove with floss.

All of these examples sound really gross. But biofilms are actually a natural form of living for both healthy and pathogenic bacteria.

How does a biofilm function?

Conceptually, it’s helpful to think of a biofilm-like apartment building. The extracellular polymeric substance (EPS) of the biofilm is like the structure or the walls of the building — it protects those living inside from the outside environment.

The bacteria live inside its walls, grow, and reproduce. There are even channels in the EPS that provide nutrients and water to the inhabitants living inside (like plumbing or a delivery service). As you can imagine, many bacteria prefer living in the safety and comfort of these communities rather than braving the elements in the outside world. 

Why do biofilms form?

Biofilms are usually produced by specific bacteria or fungi. Biofilm formation typically happens when a microbe (like Gardnerella) adheres to a surface and anchors itself to a specific physical location. In your vaginal tract, a biofilm will typically stick to the vaginal epithelium (the layer of mucosal tissue lining your vaginal canal). 

From there, the microbe can stay put and replicate in one spot, growing into a “colony” of multiple microbes.

Along the way, the microbes will produce extra proteins and other scaffolding to help anchor themselves to that physical location as they multiply. Other species of microbes may become either intentionally or unintentionally stuck in the slimy biofilm matrix as well. 

When you’re a microbe in a biofilm, expansion is your endgame. That’s why periodically, some bacteria in this community will leave to move to other sites and start new communities. This is called dispersion and it can affect your vaginal health because it means that the amount of disruptive bacteria or yeast in your vaginal microbiome is increasing.

To add insult to injury, if you have low levels of protective bacteria (like Lactobacilli) in your vaginal microbiome, it likely means that those disruptive microbes have even more space to settle down because the Lactobacilli aren’t taking up space on the vaginal wall. 

How does vaginal biofilm affect my vaginal microbiome?

In general, the term “biofilm” comes up most often in the context of vaginal infections when we’re talking about either bacterial vaginosis or yeast infections. 

This is because both bacteria and fungi can develop biofilms inside the vagina, specifically on the vaginal wall or as clumps of microbes in the mucus that lines the vagina. 

Biofilms contribute to persistent and recurrent infections because they protect the bacteria living inside them. Bacteria living in biofilms are often resistant to antibiotics because the antibiotics simply can’t reach the bacteria living inside the biofilm’s EPS (just like a house protects you from external forces like strangers or the weather). 

If a biofilm isn’t properly cleared, then some bacteria will leave the biofilm and move on to infecting other sites in the vaginal microbiome through dispersion. This can lead to recurrent infections because the disruptive microbes are spreading, growing, and re-colonizing the vaginal microbiome. 

Biofilms and bacterial vaginosis

Bacterial vaginosis is caused when there is an overgrowth of disruptive bacteria in your vaginal microbiome, also known as dysbiosis. 

A vaginal microbiome in dysbiosis often manifests as low levels of protective Lactobacillus and higher levels of disruptive bacteria like Gardnerella vaginalis, Prevotella, Atopobium, and Mobiluncus. 

This bunch of disruptive bacteria is affectionately and collectively referred to as BV-associated bacteria. 

BV-associated bacteria are prone to biofilm formation, especially Gardnerella. A 2005 study found that BV-associated bacteria and G. vaginalis were located physically near one another and formed an adherent biofilm on the surface of vaginal epithelial cells. 

Researchers currently believe that G. vaginalis starts making the bacterial biofilm and then over time, other microbes attach and flourish. And then — you guessed it — bacterial vaginosis can come back or, equally as frustrating, it never went away in the first place. 

‍Notably, a 2019 study found that anaerobic microbes (microbes that don’t like oxygen) which are often correlated with bacterial vaginosis, tend to be found at the bottom of biofilms, where they are physically removed from oxygen by the pile of other microbes on top of them.

This, along with the fact that biofilms can protect G. vaginalis from lactic acid and hydrogen peroxide, helps explain why G. vaginalis and other anaerobic bacteria tend to form biofilms — to protect themselves and ensure their own survival. 

Wondering if you have G.vaginalis or other bacterial species disrupting your vaginal microbiome? The Evvy Vaginal Health Test tests for all bacteria and fungi in your microbiome — including those that research has shown to produce bacterial biofilm. Depending on your results, our clinical care platform can also connect you to innovative prescription treatments tailored to fight those microbes.

Biofilms and yeast infections

Like bacterial vaginosis, vaginal yeast infections, sometimes called “vulvovaginal candidiasis” (VVC for short), have also been associated with biofilms. 

We know that Candida albicans, the yeast that usually causes vaginal yeast infections, can form a biofilm on the surface of vaginal mucus.

Additionally, different species of vaginal Candida have been shown to form biofilms in the lab, indicating that they may form biofilms inside the vagina as well.  

What is still unclear, though, is whether or not vaginal yeast infections require yeast to form a biofilm, or if this is just an interesting phenomenon we can see in the lab. 

The answer is likely a gray area rather than a clear yes or no — biofilms can potentially explain why 5-8% of women with a yeast infection have recurrent infections that won’t go away with typical treatment. 

Research has shown that boric acid can help with yeast infections, especially those caused by non-albicans species of Candida.  But before you jump to boric acid as a solution for your recurrent infections, test your vaginal microbiome to determine the types of bacteria and fungi in it and get a personalized plan optimized for your unique microbiome. 

How do I get rid of a biofilm?

This question of how to rid ourselves of biofilms pops up everywhere from medical devices to cleaning products and environmental hazards. Fortunately, for the case of vaginal infections, there are a few concrete starting points to work with. The first step is to know what type of microscopic organism you’re dealing with. 

Antifungals won’t work on bacteria, and not all antibiotic treatment works on yeast infections. An Evvy test is the surest way to know all the microorganisms present in your vagina, and whether or not those microbes produce biofilm.

Once you know if you’re dealing with biofilm-forming microbes, you should discuss treatment options with your doctor, including boric acid. 

FAQ

Is biofilm a yeast?

No, biofilms are structures that protect the microorganisms living inside them. Yeast can form a biofilm, though.

What triggers biofilm?

Vaginal biofilms develop when bacteria or yeast cling to the vaginal walls and form a protective layer that helps them survive. This can happen when certain bacteria, like G. vaginalis (associated with bacterial vaginosis), start to outnumber the good ones, such as Lactobacilli. Changes in the vaginal environment, like hormonal fluctuations, sexual activity, or antibiotic use, can make the vaginal pH less acidic, which can encourage the growth of harmful bacteria. When this happens, it disrupts the natural defenses, allowing these bacteria to settle in layers and form a biofilm. This biofilm can make it tougher for the immune system and treatments to tackle the infection effectively.

How do you treat biofilm bacteria?

Dealing with vaginal biofilms can be tricky, and often requires a multi-faceted approach. Biofilms can shield bacteria, making it tougher to eliminate infections with standard treatments. The first step is to find out which specific bacteria strain is causing the issue because antibiotics and antifungals work best when targeting the right fungal or bacterial species. Since biofilms can make bacteria resistant to treatment, combining different methods can help. One option is using boric acid suppositories. These can help break down biofilms and create an environment that isn’t friendly to bacteria by lowering vaginal pH, which can boost the effectiveness of antibiotics.