A guide to Lactobacillus crispatus in the vaginal microbiota

Detecting Lactobacillus crispatus may be compatible with a vaginal microbiota dominated by lactobacilli and may be associated with a lower likelihood of bacterial vaginosis. However, its presence or absence on its own does not diagnose or explain symptoms.

In summary:

• Lactobacillus crispatus is a lactobacillus species that may form part of a vaginal microbiota dominated by lactobacilli.
• Communities dominated by Lactobacillus crispatus may be associated with a lower likelihood of bacterial vaginosis, without demonstrating individual causality.
• A vaginal microbiota analysis provides context on microbial composition, but does not replace assessment by a healthcare professional.
• Interpretation should consider the overall microorganism profile, possible indicators of bacterial vaginosis, and each person’s clinical context.

If you have symptoms or questions about a result, find out more about the scope of Xenogene’s vaginal microbiota analysis and review it with your healthcare professional.

What is Lactobacillus crispatus and what role might it play in the vaginal microbiota?

Lactobacillus crispatus is a species of lactobacillus that may be part of a vaginal microbiota dominated by lactobacilli and produce lactic acid; however, finding it in a sample does not, on its own, determine the clinical status of the vagina, rule out other alterations or constitute a diagnosis.

Lactic acid is a substance produced by some bacteria that contributes to the acidity of the vaginal environment. The role of L. crispatus should be understood as part of a complete microbial community, not as that of an isolated microorganism. A recent trial studied an intervention based on this species and its possible influence on the vaginal microbiome, but its results do not make detection of the species an individual clinical marker (npj Biofilms and Microbiomes, 2025).

For this reason, a report should assess the overall composition of the sample and each person’s context. To integrate different biological data, you can consult the integrated microbiome profiles.

What is the relationship between Lactobacillus crispatus and bacterial vaginosis?

According to the literature reviewed, vaginal communities dominated by Lactobacillus crispatus have been associated with a lower likelihood of showing profiles consistent with bacterial vaginosis. However, this association does not prove that the species alone prevents bacterial vaginosis, nor does it allow an individual diagnosis to be established.

The available evidence should be interpreted with caution. A systematic review published in 2025 evaluated probiotic strategies for treating bacterial vaginosis and preventing recurrences, but its findings do not make the detection of L. crispatus a sufficient clinical marker (systematic review on probiotics and bacterial vaginosis).

In addition, a 2025 randomized trial studied a synbiotic based on several strains of L. crispatus, not the isolated presence of this species as a diagnostic test. For this reason, it is advisable to assess the microbial community as a whole, symptoms and clinical tests. Assisted clinical interpretation can help put a report into context, but it does not replace a healthcare professional.

How should a Lactobacillus crispatus result be interpreted in a vaginal microbiota analysis?

A Lactobacillus crispatus result should be interpreted alongside the relative abundance of other microorganisms, the indicators in the report, symptoms, medical history and medication. Detecting a species does not amount to a diagnosis of bacterial vaginosis, nor does it by itself rule out other causes of vaginal discomfort.

To assess it in an orderly way:

• Confirm the scope of the test: sample, method, microorganisms assessed and whether relative abundances are reported.
• Review the overall picture: assess whether lactobacilli predominate and which other microorganisms are present, without turning a percentage into a diagnosis.
• Relate the finding to the clinical picture: odour, discharge, irritation, recurrences, recent antibiotic use, menstruation or hormonal changes may affect its interpretation.
• Consult a healthcare professional: especially if there are symptoms or discordant results; professionals can review reports with support from access for healthcare professionals.

The 2025 systematic review of probiotics for bacterial vaginosis examines interventions and recurrence prevention, but it does not make the individual detection of L. crispatus a diagnostic test.

Can a vaginal microbiota analysis diagnose bacterial vaginosis?

A vaginal microbiota analysis cannot diagnose bacterial vaginosis on its own: it describes the microbial composition of the sample, while the clinical assessment should incorporate symptoms, examination, and validated clinical or microbiological tests, interpreted by a healthcare professional in the context of each person.

The result can provide insight into the balance between lactobacilli and other microorganisms, but the presence or absence of Lactobacillus crispatus does not constitute a diagnosis. The review on bacterial vaginosis and probiotics highlights the complexity of assessing this condition and its recurrences according to the 2025 systematic review.

If the report shows a profile compatible with vaginal dysbiosis, it should be reviewed alongside symptoms, medical history, medication, and the indicated tests. Interpretation assisted by Sophia, the clinical AI can help organise the information in the report, but it does not replace a healthcare professional’s decision.

What should someone with symptoms consistent with bacterial vaginosis do?

If you notice odour, changes in discharge or discomfort consistent with bacterial vaginosis, seek assessment from a healthcare professional to confirm the cause and decide on appropriate management. Do not start treatment on your own based solely on whether Lactobacillus crispatus is detected, since a microbiota result provides context but does not replace a clinical assessment.

These symptoms can have different causes, so it is useful to describe when they began, whether they recur and which medicines or vaginal products have been used. If you already have a report, take it to your appointment so it can be interpreted alongside your symptoms and medical history, without treating an isolated finding as a diagnosis.

Research into probiotics and bacterial vaginosis is still examining which regimens may be useful, so probiotics should not replace medical assessment or be used as a basis for self-medication. For further information, see our other microbiota articles.

Frequently asked questions

Does the absence of Lactobacillus crispatus mean that bacterial vaginosis is present?

No. The absence of Lactobacillus crispatus alone cannot establish that bacterial vaginosis is present. Assessment should take into account symptoms, examination and clinical or microbiological tests, as well as the overall composition of the sample. A microbiota result can provide context, but it does not replace assessment by a healthcare professional.

What is the difference between a vaginal microbiota test and a clinical test for bacterial vaginosis?

A clinical test for bacterial vaginosis assesses a clinical presentation through healthcare evaluation and validated clinical or microbiological methods. A microbiota analysis describes the microorganisms detected and their proportions according to the method used. The two results are not interchangeable: sequencing may add context, but it does not automatically turn a microbial profile into a diagnosis.

Can probiotics increase Lactobacillus crispatus?

The available evidence does not allow us to say that probiotics predictably increase Lactobacillus crispatus in every person. A 2025 systematic review examined probiotic regimens for bacterial vaginosis and recurrence prevention, and a 2025 trial evaluated a synbiotic based on several strains. These studies do not justify self-medication or guarantee an individual effect.

Can the vaginal microbiota change after antibiotics, menstruation or sexual intercourse?

The sources available for this article do not allow us to determine how much the vaginal microbiota changes after antibiotics, menstruation or sexual intercourse, or to predict the effect in a specific person. For this reason, a result should be interpreted in light of the timing of sample collection, symptoms, medical history and assessment by a healthcare professional.

See the Xenogene vaginal microbiota analysis to learn what information it can provide and discuss it with your healthcare professional.

Sources

• Effective probiotic regimens for bacterial vaginosis treatment and recurrence prevention: A systematic review — Narra J — 2025-04-01
• Impact of a multi-strain L. crispatus-based vaginal synbiotic on the vaginal microbiome: a randomized placebo-controlled trial — npj Biofilms and Microbiomes — 2025-08-09