Most Healthy Women Lack the Lactobacillus-Dominant Cervical Microbiome

If you have been told your vaginal or cervical microbiome test looks abnormal because it is not dominated by Lactobacillus, a new study complicates that verdict. Researchers in Kazakhstan sequenced the full cervical microbial community, bacteria, viruses, fungi, and even archaea, in 92 healthy women with no infection and no abnormal cervical cells, and found that the standard definition of a normal cervical microbiome does not fit most of them. The findings do not prove anything is wrong or right; they suggest the reference standard itself may be too narrow for the women it is applied to.

Key Takeaways

• Core finding: In 92 HPV-negative, cytologically normal women, 51 (55%) had cervical microbiomes not dominated by Lactobacillus, the pattern Western labs typically flag as dysbiotic, yet none showed signs of infection or disease.
• Real-world implication: Average Lactobacillus abundance across the group was just 20.58%, far below the 70%+ threshold commonly used to define a healthy vaginal or cervical microbiome, meaning current reference ranges could be misclassifying healthy people, especially outside Western study populations.
• Headline caveat: This is a single, modest snapshot study from one country, Kazakhstan; it shows these microbial differences exist, not that they are harmless (or harmful), and it cannot establish cause and effect.

Cervical Microbiome Mapped Across Bacteria, Viruses, Fungi and Archaea

A team led by A. Rakhmankulova, S. Kozhakhmetov, A. Kovenskiy and colleagues, publishing in Frontiers in Microbiology, profiled the cervical microbiome in unusual depth. Instead of looking only at bacteria, as most vaginal microbiome research does, the team took a multi-kingdom approach: sequencing bacteria, viruses, fungi, and archaea (single-celled microbes distinct from bacteria, more commonly associated with extreme environments like hot springs) together from the same cervical samples. The 92 participants were all HPV-negative with normal cervical cytology (no abnormal cell changes on screening), meaning none had signs of infection or precancerous change. Based on each woman's bacterial profile, the researchers sorted the cohort into three community state types, or CSTs, a classification system microbiologists use to group vaginal and cervical bacterial communities by which species dominate. The headline result: 51 of the 92 women, just over half, fell into community types not dominated by Lactobacillus, the bacterial genus long treated as the hallmark of a healthy cervical environment.

Cervical Health Screening Standards May Miss Healthy Variation

For anyone navigating gynecological care, reproductive health decisions, or a cervical screening result, this finding cuts against a common clinical shorthand: low Lactobacillus equals cause for concern. Clinicians and labs frequently use Lactobacillus dominance, often defined as 70% or more of the bacterial community, as the benchmark for a healthy vaginal or cervical microbiome, a threshold drawn largely from studies of Western, largely White populations. In this Kazakhstan cohort, average Lactobacillus abundance across all 92 women was just 20.58%, far under that benchmark. Because dysbiosis labels carry real clinical weight in HPV and cervical cancer risk discussions, a woman with no infection and no abnormal cytology could still be told her microbiome looks abnormal if judged against the Western reference range, even though nothing in this study shows she is unhealthy.

Three Community State Types Emerged From the Data

The credibility of this finding rests on a deliberately broad methodology. Instead of restricting analysis to bacteria through standard 16S sequencing, the researchers used multi-kingdom sequencing to capture bacterial, viral, fungal, and archaeal DNA from the same cervical swabs, then layered on functional pathway analysis, an approach that infers what the microbes are metabolically doing, not just which ones are present. All 92 participants were pre-screened to exclude both HPV infection and abnormal cytology, isolating a genuinely healthy population rather than mixing in women with undiagnosed disease. Sorting bacterial profiles into three community state types let the team ask whether diversity, and how the four microbial kingdoms interacted with each other, differed by group. It did: the three types differed significantly in microbial diversity and in the complexity of their cross-kingdom interaction networks, and the researchers identified 64 distinct functional microbial pathways significantly associated with community type, a resolution single-kingdom bacterial studies cannot offer.

A Non-Lactobacillus Result May Not Mean Trouble

If a cervical or vaginal microbiome test comes back showing low Lactobacillus, this study is a reason to ask a clinician what specific evidence, beyond the lab reference range, points to an actual problem, rather than treating a non-Lactobacillus reading as an automatic red flag. That question matters most for women without symptoms, infection, or abnormal cytology, the same profile as everyone in this cohort. The study says nothing about what a non-Lactobacillus-dominated microbiome means for someone who does have symptoms, an active infection, or an HPV-positive result, and it should not be read as license to ignore those situations. The women in the non-Lactobacillus-dominant groups were not sick by any measure the study used, but that does not mean every non-Lactobacillus profile everywhere is automatically benign; it means the current one-size-fits-all reference standard may not travel well across populations.

One Population Snapshot Cannot Prove Cause and Effect

The central limitation is built into the study's design: it is cross-sectional, meaning each woman was sampled once, at a single point in time. That structure can show three community types exist and differ statistically, but it cannot show whether any of those differences cause, prevent, or have no bearing on future health outcomes, since no one was followed forward in time. The subgroups behind the community-type comparisons were also modest, ranging from 19 to 51 women per group, and the entire cohort came from one country, Kazakhstan, so it remains unknown whether the same 20.58% average Lactobacillus figure would appear in other, more diverse populations. The authors themselves describe their cross-kingdom network findings, the patterns describing how bacteria, viruses, fungi, and archaea interact within each community type, as hypothesis-generating: results worth testing further, not conclusions ready to guide clinical decisions.

Multi-Kingdom Microbiome Research Moves to Longitudinal Studies

The study does not give a timeline for follow-up work, but its design points to the obvious next steps: longitudinal research that tracks the same women over time to see whether community type predicts later infection, HPV acquisition, or cervical cell changes, and replication in other populations to test whether the 20.58% average Lactobacillus abundance and the 64 associated pathways hold up outside Kazakhstan. In the meantime, the more immediate, actionable shift is in how reference ranges get built: multi-kingdom, population-diverse baseline data like this could eventually feed into revised clinical thresholds, so a lab report reflects normal variation across different populations of women rather than a single, Western-derived standard applied everywhere.

Common Questions

What is a multi-kingdom microbiome study?

It sequences all four major groups of microbes together, bacteria, viruses, fungi, and archaea, from the same sample, instead of profiling bacteria alone the way most vaginal and cervical microbiome research traditionally has.

Does low Lactobacillus in a cervical or vaginal microbiome test mean something is wrong?

Not necessarily. In this study, 51 of 92 women with no infection and normal cervical cytology had microbiomes not dominated by Lactobacillus, though the study cannot say whether that pattern is risk-neutral for every individual or every population.

What are community state types?

Community state types, or CSTs, are a classification system that groups vaginal and cervical bacterial communities by which species dominate; this study identified three distinct types among 92 healthy women.

Should I bring this study up with my doctor?

If you have been told your microbiome looks abnormal based on low Lactobacillus alone, it is reasonable to ask what other evidence, such as symptoms, infection markers, or cytology results, supports that assessment, since this research suggests reference ranges built on Western cohorts may not fit every population.

References

1. Aidana Rakhmankulova, Samat Kozhakhmetov, Artur Kovenskiy, et al. (2026). Multi-kingdom cervical microbiome structure in health and dysbiosis: a cross-sectional study from Kazakhstan. Frontiers in Microbiology. https://doi.org/10.3389/fmicb.2026.1836889
2. Eleni Dubé‐Zinatelli, Luna Cappelletti, Nafissa Ismail (2024). Vaginal Microbiome: Environmental, Biological, and Racial Influences on Gynecological Health Across the Lifespan. American Journal of Reproductive Immunology. https://doi.org/10.1111/aji.70026
3. Wojciech Kwasniewski, Maria Wolun‑Cholewa, Jan Kotarski, et al. (2018). Microbiota dysbiosis is associated with HPV‑induced cervical carcinogenesis. Oncology Letters. https://doi.org/10.3892/ol.2018.9509
4. Diversity in women and their vaginal microbiota. sciencedirect.com. https://www.sciencedirect.com/science/article/pii/S0966842X24003287