The bacterial biofilm: why your BV keeps coming back


BiofilmBacterial biofilms occur all throughout nature, being one of the best ways for a bacteria to form a strong colony without having to be everywhere at once, and without being washed away easily.

Recurrent bacterial vaginosis (BV) exists because one or more bacteria have made a biofilm on your vaginal cells, which creates an impenetrable layer that most treatments, like antibiotics, cannot get underneath. This means your treatments kill the planktonic, free-floating bacteria, but do not touch the core bacteria in the biofilm.

(How to get rid of the biofilm in recurrent BV – Killing BV – to resolve chronic BV.)

What is a bacterial biofilm?

A bacterial biofilm may occur in a wound, preventing healing, and can grow around medical implants and catheters, forming thick layers that stick closely to surfaces. Dental plaque is a biofilm, which is why it can get scraped off – and always grows back (the bacteria in your mouth don’t change that much).

The biofilm is a living shield of bacteria and protein matrix stuck to the vaginal walls, keeping other bacteria as easily-managed planktonic bacteria – good or bad, it doesn’t matter. All bacteria work by producing substances that are destructive to other competitive bacteria (bacteriocins, biofilms) and by binding to the vaginal cells, providing a physical barrier to competitive bacteria.

The BV biofilm

The Gardnerella vaginalis (or other bacterial) biofilm is by its very nature resistant – but not completely immune – to the hydrogen peroxide and lactic acid produced by the lactobacilli. Frustratingly the G. vaginalis biofilm is also resistant to high levels of antibiotics. This is why hydrogen peroxide, apple cider vinegar, boric acid, antibiotic creams, gels and pastes, and whatever else you have been sticking up your vagina so far has not cured your BV – it cannot break down the biofilm by itself.

Why don’t antibiotics work on the biofilm?

Antibiotics do not reduce the biofilm; they simply put it into a dormant state with a couple of bullet holes in it, so when you stop taking antibiotics, the problem returns as if nothing happened. Bacteria are infinitely clever in this way. The biofilm is like a protective living cocoon, which quite frankly is an ingenious evolutionary survival trick, but only when it’s being used for good, not evil.

When you have bacterial vaginosis, the number and type of lactobacilli are not sufficient to fight the biofilm. The alkaline state of your BV-affected vagina lacks the acidity lactobacilli need to survive in any meaningful numbers. Trying to get lactobacilli to survive in a BV-affected vagina is like asking us to breathe underwater: it doesn’t work. They can’t survive.

This is where tackling your biofilm problem thoroughly is of critical importance. Otherwise, you will have BV forever. (See Killing BV)

The different states of G. vaginalis that result in the biofilm

Gardnerella vaginalis comes in two forms: planktonic (free-floating) and cohesive (biofilm seed type). Planktonic Gardnerella vaginalis has not been shown to be clinically significant in BV; it is the cohesive Gardnerella vaginalis that is the real problem.

Cohesive Gardnerella is the kind that creates the biofilm, and then other bad bacteria become part of this biofilm because it provides them protection. This protective biofilm is a thick, slimy, bacteria-laden barrier to Lactobacillus.

Here’s what we know about the Gardnerella biofilm:

  • Bacterial vaginosis is a polymicrobial biofilm infection (many microbes are responsible, working together in a team, not just one single species)
  • Gardnerella vaginalis may be the initial species to adhere to the vaginal epithelium, and is then subsequently adhered to by other species
  • Not all forms of Gardnerella vaginalis form biofilms, with only the cohesive version doing so, though the difference might only be a change in the mode of growth
  • Gardnerella is sexually transmitted between infected male-female and female-female partners
  • Efforts should be put towards finding biofilm-breaking treatments for BV (which we’re working on)


Read the full review of researchers’ findings on the BV biofilm, The biofilm in bacterial vaginosis: implications for epidemiology, diagnosis and treatment, Hans Verstraelen and Alexander Swidsinskib, 2013, Current Opinion in Infectious Diseases.