Women’s Health, Vaginal Microbiome, Recurrent BV, Thrush, UTIs

Vaginal Dysbiosis: Why BV, Thrush and UTIs Can Keep Coming Back

If you keep experiencing bacterial vaginosis (BV), thrush, urinary tract infections (UTIs) or vaginal symptoms that return after treatment, you may have heard the term vaginal dysbiosis.

But what does it actually mean?

Vaginal dysbiosis describes a change in the vaginal microbial ecosystem. In many women, this involves a reduction in protective Lactobacillus species and an increase in other microorganisms.

Dysbiosis is particularly well established in conditions such as bacterial vaginosis. The relationship is more complex in recurrent thrush, aerobic vaginitis and recurrent UTI, where multiple factors can contribute.

This distinction matters.

Not every recurrent vaginal or urinary problem is caused by dysbiosis, and finding an organism on a vaginal microbiome test does not automatically mean it is causing disease.

But for women with persistent or recurrent symptoms, understanding the vaginal environment can sometimes provide another important piece of the clinical picture.

What Is the Vaginal Microbiome?

The vaginal microbiome is the community of microorganisms living within the vagina.

It is not static.

The vaginal microbial environment can change in response to:

• hormonal changes

• menstruation

• sexual activity

• semen exposure

• antibiotics

• pregnancy

• menopause

• vaginal products

• infection

• other biological and environmental factors

In many reproductive-aged women, Lactobacillus species dominate the vaginal microbiome.

Important species include:

• Lactobacillus crispatus

• Lactobacillus gasseri

• Lactobacillus jensenii

• Lactobacillus iners

These organisms are not interchangeable.

Different Lactobacillus species have different biological characteristics, and different vaginal microbial communities can behave differently over time.

Why Are Lactobacilli Important?

Lactobacilli are an important component of many healthy vaginal microbial communities.

They produce lactic acid, which contributes to maintaining an acidic vaginal environment.

An acidic environment can help limit the growth or colonisation of some potentially disruptive organisms.

Lactobacilli may also influence the vaginal environment through competitive interactions with other microorganisms and additional antimicrobial mechanisms.

However, vaginal health cannot be reduced to a simple equation of more Lactobacillus equals healthy and less Lactobacillus equals disease.

There is significant variation between women.

Some asymptomatic women have vaginal microbial communities that are not strongly Lactobacillus-dominant.

Clinical context matters.

What Are Vaginal Community State Types?

Researchers often describe vaginal microbiomes using Community State Types, or CSTs.

These are broad patterns based on which bacterial communities predominate.

Commonly described CSTs include:

• CST I — predominantly Lactobacillus crispatus

• CST II — predominantly Lactobacillus gasseri

• CST III — predominantly Lactobacillus iners

• CST IV — lower Lactobacillus abundance with a more diverse microbial community

• CST V — predominantly Lactobacillus jensenii

CSTs are useful research tools for understanding different vaginal microbial patterns.

They are not diagnoses.

For example, CST IV describes a diverse microbial community but does not automatically mean that a woman has bacterial vaginosis or requires treatment.

Likewise, identifying a particular Lactobacillus-dominant CST does not guarantee that someone will never experience symptoms.

What Is Vaginal Dysbiosis?

Vaginal dysbiosis generally refers to a disruption or shift in the vaginal microbial ecosystem.

This may involve:

• reduced Lactobacillus dominance

• increased microbial diversity

• over-representation of particular organisms

• altered vaginal pH

• changes in microbial interactions

But vaginal dysbiosis is not one single diagnosis.

It is better understood as a description of the microbial environment.

That environment needs to be interpreted alongside the condition being investigated.

Is Vaginal Dysbiosis a Diagnosis?

Not in the same way that BV, vulvovaginal candidiasis or UTI are diagnoses.

This is an important distinction.

Bacterial vaginosis is a recognised clinical condition characterised by a shift away from Lactobacillus-dominant flora toward a polymicrobial anaerobic community.

Aerobic vaginitis is a distinct inflammatory vaginal condition assessed using clinical and microscopic features, including lactobacillary grade, leukocytes, toxic leukocytes, parabasal cells and background flora.

Vulvovaginal candidiasis involves symptomatic disease associated with Candida and needs to be interpreted in the context of compatible symptoms and appropriate testing.

Urinary tract infection is an infection of the urinary tract and should be assessed using urinary symptoms and urine testing or culture where clinically appropriate.

Vaginal dysbiosis, by contrast, describes a microbial pattern.

It may provide useful information, but it should not replace diagnosis of the condition actually causing symptoms.

How Is Vaginal Dysbiosis Connected to Bacterial Vaginosis?

BV is where the dysbiosis connection is strongest.

In BV, protective Lactobacillus populations are often reduced and replaced by a diverse community of BV-associated anaerobic organisms.

These can include organisms such as:

• Gardnerella species

• Fannyhessea vaginae

• Prevotella species

• Mobiluncus species

• Megasphaera species

• Sneathia species

• BV-associated bacteria such as BVAB-2

BV-associated bacteria can also form polymicrobial biofilms, particularly involving Gardnerella species.

This may contribute to persistence and recurrence in some women.

BV is therefore much more than simply finding Gardnerella on a test.

Gardnerella can sometimes be detected in women without symptomatic BV.

The overall microbial pattern, symptoms and appropriate diagnostic findings matter.

Why Can BV Keep Coming Back?

BV has a high recurrence rate following treatment.

Several factors may contribute, including:

• persistence of BV-associated microbial communities

• biofilm

• failure to re-establish a stable Lactobacillus-dominant environment

• sexual exposure and exchange of BV-associated organisms

• menstruation

• semen-associated changes in vaginal pH

• individual vaginal microbial characteristics

Recent evidence has also changed how we understand sexual partnerships in recurrent BV.

BV is not traditionally classified as a conventional sexually transmitted infection, but sexual activity and sexual partnerships are strongly associated with BV.

Evidence increasingly supports exchange of BV-associated bacteria between ongoing sexual partners.

Australian STI guidance now recommends concurrent treatment of an ongoing or regular partner with a penis when a person with vaginal BV is being treated.

This represents an important change in recurrent-BV management.

What About Recurrent Thrush?

Recurrent vulvovaginal candidiasis, often called recurrent thrush, is different from BV.

Candida can exist in the vagina without causing symptoms.

Vulvovaginal candidiasis occurs when Candida is associated with compatible symptoms and clinical findings.

Recurrent vulvovaginal candidiasis generally involves repeated symptomatic episodes and may require confirmation of the organism involved.

Candida albicans causes most cases, but non-albicans species such as Candida glabrata can also occur and may respond differently to treatment.

The relationship between Candida and the vaginal microbiome is complex.

Recurrent thrush should not simply be interpreted as a lack of Lactobacillus.

This is one reason why repeated antifungal treatment without confirming what is actually present can become problematic.

If symptoms keep returning, Candida speciation and appropriate diagnostic assessment may become particularly important.

What About Aerobic Vaginitis?

Aerobic vaginitis (AV) is another condition that can be confused with BV or thrush.

It is associated with vaginal inflammation, disruption of Lactobacillus populations and a shift toward aerobic or facultative organisms.

Organisms associated with AV can include:

• Escherichia coli

• Enterococcus species

• Staphylococcus aureus

• Streptococcus agalactiae (Group B Streptococcus)

However, finding one of these organisms on a comprehensive molecular vaginal microbiome test does not automatically mean someone has aerobic vaginitis.

AV is an inflammatory condition.

Established assessment described in the literature uses microscopy to evaluate factors such as lactobacillary grade, leukocytes, toxic leukocytes, parabasal cells and background flora.

Molecular testing can provide useful additional information about which organisms are present and Lactobacillus composition, but results need to be interpreted in clinical context.

What Is the Connection Between the Vaginal Microbiome and Recurrent UTIs?

The vagina and urinary tract are anatomically and biologically interconnected.

The gastrointestinal tract is an important reservoir for uropathogens such as E. coli, and the vaginal and periurethral environment can provide a pathway through which organisms reach the urinary tract.

Research has demonstrated associations between vaginal microbial composition and susceptibility to UTI.

In some women, vaginal colonisation with uropathogens such as E. coli may be one factor contributing to recurrent UTI risk.

However, recurrent UTI is multifactorial.

Sexual activity, antimicrobial resistance, hormonal changes, urinary tract factors, diabetes, bladder emptying and other clinical factors may also contribute.

A vaginal microbiome result therefore does not diagnose a UTI and should never replace urine culture or appropriate urinary assessment.

How Do Hormones Affect the Vaginal Microbiome?

Oestrogen has an important relationship with the vaginal environment.

It supports the vaginal epithelium and promotes glycogen accumulation, helping create conditions favourable to Lactobacillus species.

During perimenopause and menopause, declining oestrogen can lead to changes in:

• vaginal tissues

• vaginal pH

• lubrication

• Lactobacillus abundance

• microbial composition

• urinary and vaginal symptoms

Some women develop symptoms associated with Genitourinary Syndrome of Menopause (GSM).

These may include:

• vaginal dryness

• burning

• irritation

• painful sex

• urinary urgency

• urinary frequency

• discomfort with urination

• recurrent UTIs

Importantly, these symptoms can mimic infection.

A woman experiencing burning and urinary frequency may assume she has another UTI when cultures are negative.

Likewise, vaginal irritation may be repeatedly treated as thrush when another cause is responsible.

Hormonal context therefore matters when interpreting recurrent symptoms and microbiome results.

Can Antibiotics Affect the Vaginal Microbiome?

Yes.

Antibiotics are essential treatments for many bacterial infections and should be used when clinically indicated.

However, antimicrobial exposure can also affect commensal microbial communities.

The degree of disruption depends on the antibiotic, duration, microbial community and individual patient.

This does not mean antibiotics should be avoided when they are needed.

It means recurrent symptoms should ideally be diagnosed accurately so that antimicrobial treatment is targeted appropriately rather than repeatedly prescribed empirically.

What Can Comprehensive Vaginal Microbiome Testing Show?

Standard vaginal testing remains important for diagnosing common vaginal infections and sexually transmitted infections where appropriate.

In selected women with persistent or recurrent symptoms, comprehensive molecular vaginal microbiome testing can provide additional information about the vaginal microbial environment.

This DNA-based testing may provide information about several different areas.

Lactobacillus Composition

Testing may identify the abundance and species composition of Lactobacillus organisms.

This can help characterise whether the microbial community is strongly Lactobacillus-dominant or more diverse.

BV-Associated Organisms

Molecular testing can identify a range of organisms associated with BV and provide information about their relative abundance or quantity, depending on the assay.

This can help characterise an anaerobic dysbiosis pattern.

Aerobic Organisms

Testing may identify organisms such as E. coli, Enterococcus, Staphylococcus or Streptococcus species.

These findings may be clinically relevant in some situations.

However, detecting these organisms does not automatically diagnose aerobic vaginitis.

Candida Species

Testing may identify Candida and, depending on the assay, distinguish between species.

This can be particularly useful when recurrent symptoms have not responded as expected to standard antifungal treatment.

Sexually Transmitted Infections

Depending on the panel used, comprehensive molecular testing may also include selected recognised sexually transmitted infections.

STI results need to be interpreted and managed according to established sexual-health guidance.

Other Organisms

Comprehensive panels may detect other organisms whose clinical significance varies substantially depending on symptoms and clinical context.

Detection does not automatically mean treatment is required.

This is particularly important for organisms that can occur as colonisers.

Detection Does Not Equal Disease

This is one of the most important principles in vaginal microbiome medicine.

Molecular testing is highly sensitive.

That can be useful — but it also means microorganisms may be detected that are not responsible for symptoms.

A test result should therefore never be interpreted simply as organism detected equals organism causing disease equals organism must be eradicated.

Instead, results need to be considered alongside:

• symptoms

• clinical history

• vaginal pH where relevant

• standard diagnostic testing

• previous treatments

• hormonal status

• sexual history where clinically relevant

• urine cultures where urinary symptoms are present

• the overall microbial pattern

The purpose of testing is not to sterilise the vagina.

A healthy vagina contains microorganisms.

The goal is to understand whether the microbial findings are relevant to the clinical problem.

Does Vaginal Dysbiosis Always Cause Symptoms?

No.

Some women have diverse vaginal microbial communities without symptoms.

Others experience significant symptoms despite relatively subtle microbiome findings.

And some symptoms attributed to "dysbiosis" may actually be caused by another condition.

Persistent vaginal symptoms can also result from:

• Genitourinary Syndrome of Menopause

• vulval dermatological conditions

• irritant or contact reactions

• pelvic floor dysfunction

• sexually transmitted infections

• other forms of vaginitis

• vulvodynia

• urinary conditions

This is why microbiome testing should complement clinical assessment rather than replace it.

Why Can Recurrent Symptoms Become So Difficult to Treat?

One reason is that several different conditions can produce similar symptoms.

Burning can occur with Candida, aerobic vaginitis, GSM, vulval irritation, UTI, sexually transmitted infections, pelvic floor conditions.

Discharge can occur with BV, Candida, aerobic vaginitis, sexually transmitted infections, physiological vaginal changes.

Urinary frequency can occur with UTI, GSM, bladder pain syndrome, pelvic floor dysfunction, other urinary conditions.

If every recurrence is treated according to symptoms alone, the wrong condition may sometimes be treated.

Another challenge is that more than one condition can coexist.

For example, a woman may have hormonal changes associated with perimenopause while also experiencing recurrent BV.

Or she may have recurrent UTI alongside vaginal dysbiosis.

The goal is therefore not simply to find one explanation for everything.

It is to determine which factors are actually relevant.

My Evidence-Informed Clinical Framework

For complex recurrent vaginal and urinary presentations, I use a structured clinical framework: RESET, REBUILD, RESTORE, MAINTAIN, RESCUE.

This is the clinical framework I use to organise assessment and management over time.

It does not mean that every woman requires every intervention or that one standard protocol applies to every microbiome pattern.

Treatment remains condition-specific and individualised.

RESET

The first priority is identifying and treating active conditions where treatment is clinically indicated.

Depending on the presentation, this might involve assessment or treatment of:

• bacterial vaginosis

• vulvovaginal candidiasis

• urinary tract infection

• sexually transmitted infection

• aerobic vaginitis or another form of vaginitis

• GSM or other non-infectious contributors

Appropriate testing can be particularly important when symptoms are recurrent or previous treatment has repeatedly failed.

The aim of RESET is not to eradicate every organism detected on a microbiome test.

It is to identify what is clinically relevant and treat established disease appropriately.

REBUILD

Once an active condition has been addressed, the next question is whether there are modifiable factors affecting the vaginal environment.

This may include considering:

• unnecessary antimicrobial exposure

• vaginal or vulval irritants

• hormonal factors

• vaginal dryness

• sexual or menstrual triggers

• vaginal pH where clinically useful

• the overall Lactobacillus profile

There is considerable interest in oral and vaginal probiotic strategies.

However, probiotic evidence varies according to the condition, bacterial strain, route of administration and population studied.

Probiotics should therefore be considered selectively rather than assumed to be necessary for every woman with recurrent symptoms.

RESTORE

RESTORE focuses on supporting the vaginal environment and addressing factors that may interfere with longer-term stability.

Depending on the individual, this may involve:

• addressing Genitourinary Syndrome of Menopause

• considering vaginal oestrogen where clinically appropriate

• avoiding unnecessary vaginal products or douching

• reviewing sexual or menstrual triggers

• condition-specific prevention

• considering microbiome-directed strategies where appropriate

The goal is not to force every woman into one theoretical "perfect" microbiome.

It is to support vaginal health while addressing the factors relevant to her symptoms and recurrence pattern.

MAINTAIN

Long-term management depends on the condition involved.

There is no universal maintenance protocol for vaginal dysbiosis.

Examples of evidence-based or evidence-informed maintenance strategies may include:

• Recurrent BV prevention strategies

• Suppressive therapy for recurrent vulvovaginal candidiasis when indicated

• Vaginal oestrogen for appropriate peri- or postmenopausal women

• Recurrent UTI prevention strategies

• Reducing unnecessary antimicrobial exposure

• Monitoring symptom patterns and known triggers

Some women may also choose microbiome-supportive strategies, but these should be individualised.

RESCUE

Recurrent conditions need a plan for what happens if symptoms return.

A RESCUE plan may establish:

• Which symptoms require testing

• When treatment can reasonably begin

• When urine culture is needed

• When vaginal testing is appropriate

• When STI testing should be considered

• When symptoms suggest something different from the previous diagnosis

• When urgent or face-to-face assessment is required

The aim is to avoid repeatedly starting treatment based purely on the assumption that every recurrence is the same condition.

What If Standard Tests Keep Coming Back Normal?

Persistent symptoms with repeatedly negative standard testing deserve further assessment.

A negative test does not mean symptoms are not real. It means the particular condition assessed by that test was not demonstrated at that time.

Depending on the clinical picture, further assessment may consider:

• GSM

• Vulval conditions

• Other forms of vaginitis

• Recurrent conditions not present at the time of testing

• Urinary causes

• Pelvic floor dysfunction

• Irritant or allergic causes

• STI risk

• Vaginal microbial composition in selected cases

This is one area where a more detailed history and broader assessment can be particularly useful.

When Might Comprehensive Vaginal Microbiome Testing Be Considered?

Comprehensive molecular vaginal microbiome testing may be considered in selected women experiencing:

• Recurrent BV

• Recurrent vaginal symptoms despite previous treatment

• Recurrent thrush where the pattern or species is unclear

• Persistent vaginal symptoms with inconclusive standard testing

• Suspected vaginal dysbiosis

• Recurrent vaginal symptoms alongside recurrent urinary symptoms

• Complex symptoms where understanding Lactobacillus and microbial composition may add useful information

Testing is not necessary for every vaginal symptom. And testing should not be performed simply to identify organisms to eradicate.

The value comes from asking a specific clinical question and interpreting the result within the comprehensive clinical picture.

When Should You See a GP or Sexual Health Clinician?

Telehealth can be useful for reviewing recurrent symptoms, previous pathology, treatment history, recurrence patterns and vaginal microbiome results.

However, some presentations require face-to-face assessment.

You may be advised to see your GP, a sexual health clinician or another appropriate healthcare professional if you require:

• A physical or pelvic examination

• Examination of persistent vulval or vaginal skin changes

• Microscopy or specimen collection that cannot be completed remotely

• Cervical screening or other examination-based testing

• Assessment of pelvic pain or abnormal vaginal bleeding

• Assessment of a new lump, ulcer, lesion or unexplained genital change

• Investigation of persistent symptoms where the diagnosis remains unclear

• STI testing or examination that cannot appropriately be completed through telehealth

• Further urinary tract investigation or examination

Seek prompt medical assessment if you develop:

• Severe pelvic or abdominal pain

• Significant or unexplained vaginal bleeding

• Fever or systemic illness

• Flank or kidney pain

• Persistent vomiting

• Rapidly worsening symptoms

• Pregnancy with concerning vaginal or urinary symptoms

Telehealth has limitations, and referral for face-to-face assessment is recommended whenever examination, investigation or another level of care is clinically indicated.

A Comprehensive Approach to Recurrent Vaginal Symptoms

Recurrent BV, thrush and UTIs are frustrating partly because the same symptoms can have different causes — and several factors can coexist.

The vaginal microbiome can provide valuable information, but it is only one part of the comprehensive clinical picture.

Good assessment asks:

What condition is actually present? Are symptoms being confirmed with appropriate testing? What does the Lactobacillus profile look like? Are BV-associated or aerobic organisms relevant? Which Candida species is present, if any? Are urinary infections culture-confirmed? Are hormones influencing the vaginal environment? Are sexual, menstrual or medication-related factors contributing? Is a microbiome finding actually clinically significant?

The aim is not simply to treat a test result. It is to understand the pattern behind recurrent symptoms and develop an individualised, evidence-informed plan for treatment, prevention and recurrence.

About Kylie Sayce NP

Kylie Sayce is an Australian Endorsed Nurse Practitioner with a clinical focus on recurrent vaginal and urinary conditions, vaginal microbiome health and women's sexual and reproductive health.

The Telehealth Clinic provides Australia-wide consultations for women experiencing recurrent BV, recurrent thrush, recurrent UTIs, aerobic vaginitis, persistent vaginal symptoms and genitourinary symptoms associated with perimenopause and menopause.

For complex recurrent symptoms, consultations allow time to comprehensively review previous pathology, treatment history, recurrence patterns, hormonal factors, vaginal and urinary symptoms and, where clinically appropriate, comprehensive vaginal microbiome testing.

My approach uses an evidence-informed clinical framework: RESET, REBUILD, RESTORE, MAINTAIN, RESCUE — with management individualised according to the condition identified, clinical evidence and the patient's circumstances.