Biofilms and Recurrent BV: Why Bacterial Vaginosis Keeps Coming Back
The Hidden Role of Biofilms in Recurrent Bacterial Vaginosis
"I've taken the antibiotics. The symptoms improved. Then a few weeks later, the odour and discharge came back."
This is one of the most common stories I hear from women experiencing recurrent bacterial vaginosis (BV). Symptoms improve after treatment, only to return weeks or months later, leaving many women feeling frustrated, confused and exhausted. If this sounds familiar, you are certainly not alone.
BV is the most common cause of abnormal vaginal discharge in women of reproductive age, and recurrence is unfortunately very common. Many women will experience another episode within a few months of completing treatment. While antibiotics remain an effective and evidence-based treatment, recurrent BV is often more complex than simply having an infection that refuses to go away.
Over the last decade, research into the vaginal microbiome has identified an important factor that may contribute to recurrent BV in some women: biofilms. Understanding what biofilms are and how they interact with the vaginal environment may help explain why symptoms sometimes return despite appropriate treatment.
What Is Bacterial Vaginosis?
The vagina contains a complex ecosystem of microorganisms known as the vaginal microbiome. In many healthy reproductive-age women, this environment is dominated by beneficial bacteria called Lactobacillus. These bacteria help maintain an acidic vaginal pH and support the natural balance of the vaginal ecosystem.
BV occurs when this balance changes. Protective Lactobacillus populations decrease and other bacteria become more abundant, creating a state known as vaginal dysbiosis. Common symptoms include vaginal discharge, a strong or fishy odour, increased discharge, symptoms that worsen after sex and vaginal irritation or discomfort. Some women may have BV without experiencing any symptoms at all.
Understanding BV as a change in the vaginal microbiome rather than a simple infection helps explain why recurrence can be such a challenge for some women.
Why Does BV Keep Coming Back?
One of the biggest misconceptions about BV is that antibiotics should permanently solve the problem. While antibiotics are highly effective at reducing bacteria associated with BV, they do not always restore a healthy Lactobacillus-dominant vaginal microbiome.
For many women, symptoms improve because BV-associated bacteria have been reduced. However, if the vaginal environment remains vulnerable and protective Lactobacillus populations do not fully recover, the conditions that allowed BV to develop may still be present. This can create an opportunity for symptoms to return weeks or months later.
Researchers now understand that recurrent BV is often influenced by multiple factors, including the vaginal microbiome, hormonal influences, sexual activity, bacterial biofilms and individual susceptibility. This broader understanding has changed the way clinicians think about recurrent symptoms.
What Is a Biofilm?
A biofilm is a structured community of microorganisms that attaches to a surface and surrounds itself with a protective layer. Rather than existing as individual free-floating bacteria, microorganisms within a biofilm work together and form a highly organised community.
You can think of a biofilm as a microscopic protective shield. The bacteria live together within this structure, making them more difficult to remove and potentially less accessible to treatment. Researchers believe biofilms may play an important role in why BV can become persistent or repeatedly return in some women.
Biofilms are not unique to BV. They occur throughout nature and can develop in many different environments. However, their role within the vaginal microbiome has become an important area of research because of their potential association with recurrent symptoms.
What Do Biofilms Have To Do With BV?
Researchers have identified biofilms on the vaginal lining in women with bacterial vaginosis. One of the organisms most commonly associated with these biofilms is Gardnerella vaginalis, although BV is generally considered a condition involving multiple bacterial species rather than a single organism.
Within a biofilm, bacteria can attach firmly to the vaginal lining, multiply within a protected environment and interact with other microorganisms. This structure may help them persist despite treatment and may contribute to recurrence in some women.
While research is ongoing, biofilms are considered one of the most important discoveries in our understanding of recurrent BV. They provide a possible explanation for why symptoms may improve after treatment but later return despite appropriate management.
Why Antibiotics May Not Always Prevent Recurrence
Antibiotics remain the recommended first-line treatment for bacterial vaginosis and are often very effective at reducing BV-associated bacteria and relieving symptoms. However, recurrent BV highlights the fact that reducing bacteria is not always the same as restoring long-term balance within the vaginal ecosystem.
In some women, antibiotics successfully reduce bacteria associated with BV, symptoms improve and the infection appears to resolve. However, the vaginal microbiome may remain vulnerable if Lactobacillus populations do not fully recover. Over time, vaginal dysbiosis may develop again and symptoms can return.
This does not mean treatment has failed. Instead, it reflects the complexity of the vaginal microbiome and the multiple factors that influence vaginal health.
The Relationship Between Biofilms and the Vaginal Microbiome
The vaginal microbiome is dynamic and constantly changing. It can be influenced by hormones, sexual activity, medications, age and many other factors.
In many healthy women, Lactobacillus species dominate the vaginal microbiome. Common species include Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus gasseri and Lactobacillus iners. These bacteria help maintain an acidic vaginal environment through the production of lactic acid and contribute to the stability of the vaginal ecosystem.
When Lactobacillus populations decrease, the vaginal environment may become more favourable for bacteria associated with BV. Researchers continue to investigate how biofilms interact with these microbiome changes and whether they contribute to ongoing dysbiosis and recurrence.
This area of research is evolving rapidly and continues to improve our understanding of recurrent vaginal symptoms.
Can Sexual Activity Influence Recurrence?
BV is not classified as a traditional sexually transmitted infection. However, sexual activity can influence the vaginal environment and may contribute to recurrence in some women.
Research has identified associations between recurrent BV and factors such as new sexual partners, multiple sexual partners, female sexual partners and unprotected intercourse. Semen has a naturally higher pH than the vagina and may temporarily alter the vaginal environment, which could influence the balance of the vaginal microbiome.
Many women notice that symptoms seem to flare after sex. While this does not necessarily mean sexual activity caused the BV, it may be an important factor to consider when assessing recurrent symptoms.
What About Hormones?
Hormones play a major role in vaginal health and microbiome stability. Oestrogen supports vaginal tissue health and promotes glycogen production within vaginal cells. Glycogen acts as a fuel source that supports Lactobacillus populations and helps maintain a healthy vaginal environment.
Changes in hormone levels can influence vaginal pH, Lactobacillus populations and the overall stability of the vaginal microbiome. This may be particularly relevant during perimenopause, menopause, breastfeeding, the postpartum period and while using certain hormonal treatments.
For some women, hormonal changes may contribute to recurrent symptoms or increase susceptibility to vaginal dysbiosis.
Could It Be Something Other Than BV?
Not all recurrent vaginal symptoms are caused by bacterial vaginosis. Several conditions can cause similar symptoms, including recurrent thrush, aerobic vaginitis, cytolytic vaginosis, genitourinary syndrome of menopause (GSM), contact dermatitis and vulval pain conditions.
Some women may also experience more than one condition at the same time. This is one reason why persistent symptoms deserve a thorough assessment rather than repeatedly treating presumed BV without understanding the full picture.
A detailed history, appropriate testing and consideration of other contributing factors are often essential when symptoms continue to return.
How Is Recurrent BV Assessed?
When symptoms continue recurring, assessment often involves looking beyond a single test result. Important considerations may include symptom history, previous investigations, treatment history, hormonal influences, sexual factors, vaginal microbiome health and the possibility of alternative diagnoses.
The goal is not simply to confirm the presence of BV but to understand why symptoms are recurring and what factors may be contributing to ongoing vaginal dysbiosis.
This broader approach is often particularly important for women who have completed multiple courses of treatment without achieving lasting improvement.
What About Vaginal Microbiome Testing?
Interest in vaginal microbiome testing has increased significantly in recent years. These tests may provide information about Lactobacillus species, bacterial diversity and microorganisms associated with vaginal dysbiosis.
For some women experiencing recurrent or complex symptoms, this additional information may provide useful insight into the balance of their vaginal microbiome. However, microbiome testing remains an evolving area of medicine and should always be interpreted alongside symptoms, clinical history and standard investigations.
A test result alone does not provide a diagnosis or determine the most appropriate management plan.
The Bottom Line
Biofilms are one of the most important discoveries in our understanding of recurrent bacterial vaginosis. These microscopic bacterial communities may help explain why some women experience repeated episodes of BV despite appropriate treatment.
However, recurrent BV is rarely caused by a single factor. Changes in the vaginal microbiome, reduced Lactobacillus populations, hormonal influences, sexual factors and alternative diagnoses may all contribute to ongoing symptoms.
Understanding the underlying reasons for recurrence is often the first step towards developing a more personalised and evidence-based approach to vaginal health.
How I Can Help
I am Kylie Sayce, an endorsed Nurse Practitioner with extensive clinical experience in sexual and reproductive health and advanced training in the human microbiome.
Over the past three years, I have completed more than 30,000 telehealth consultations, including caring for women experiencing recurrent BV, recurrent thrush, hormonal changes and ongoing vaginal symptoms.
Many women who come to my clinic have experienced recurrent BV despite multiple courses of antibiotics, been told their tests are normal despite ongoing symptoms, or felt frustrated by the cycle of temporary improvement followed by recurrence.
My approach focuses on understanding your individual history, reviewing previous investigations, considering potential contributing factors and developing an evidence-based management plan tailored to your situation.
If you are experiencing recurrent BV or ongoing vaginal symptoms, you can book a consultation to discuss your symptoms and explore the next steps.
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Medical Disclaimer
This information is intended for educational purposes only and does not replace individual medical advice, diagnosis or treatment. If you are experiencing symptoms, please seek personalised advice from an appropriately qualified healthcare professional.
