Xia Zhou M.D. is currently the Research Assistant Professor in the Department of Biological Science at The Institute for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho. Dr. Zhou has was a physician at Qingdao University Medical College during 1995-2001, in China. She received her M.D. from Shandong University's School of Medicine in 1988. Dr. Zhou earned her M.S. in molecular microbiology from Qingdao University Medical College in 1999. Her research interests include human microbial ecology of urogenital tract, eco-pathogenesis of urinary tract infections and polymicrobial infections.
This new study challenges the common pieces of wisdom about microbial communities in the human vagina. Contrary to popular belief, the vaginal microbiome in healthy women changes over short periods of time, differs among individuals, and varies in its response to menses and sexual intercourse.
What did you set out to discover with your research?
The aim of this study is to characterize the natural changes of human vaginal microbiome over short periods of time using high-throughput "next generation" genomic sequencing technology and function analysis methods.
What were your most significant findings?
It is well known that the human vagina harbors an assemblage of diverse microbes. Some common beliefs in the field hold that these microbial communities are more or less the same in different women, and do not change very much over time (i.e, over months or even years). The findings from our study show that both of these pieces of common wisdom are not quite true.
Previously we showed that five kinds of microbial communities exist in the vagina of different women and these kinds are more or less prevalent depending on the ethnic background of the women. The present study confirms and extends those results and shows that the types and abundance of microbes found in the vagina can vary – sometimes dramatically – over short time intervals in some women, while in others there is no observed change. These findings have potential implications for predicting the potential risk associated with changes in the vaginal microbiome.
Changes in vaginal microbes can coincide with menses and sexual intercourse, but often do not, and these temporal shifts vary between women and seem highly personalized. This idea of personalized microbiota is critical, as most studies or treatments are based on the belief that all women are the same and that similar responses are expected from treatments. Our findings pave the way for stratifying women into groups, each of which could receive more personalized therapies.
Were these findings surprising?
Yes, the findings are very surprising.
This is the first time to clearly define the range of bacterial populations present in vaginas and characterize vaginal community function by determining the metabolites produced over short periods of time in detail using sophisticated methodologies and mathematical models. This study shows a new view of the normal vaginal microbiome, one that is complex and unique. The vaginal microbiome in healthy women changes over short periods of time, differs among individuals, and varies in its response to menses and sexual intercourse.
Most previous studies of the vaginal microbiome have employed cross-sectional study designs wherein samples are collected at a single point in time. The data and findings of these studies must now be cautiously reconsidered with full knowledge that these observations were made just once in what is often a changing landscape of microbial diversity. The implications are also far reaching in terms of the diagnostics tests currently used that rely on only one sample, and low-resolution tests that fail to take the entire set of microbes present into account.
What are the potential implications of your findings?
Our findings indicate that the stability of the vaginal communities, as well as their composition, might be important factors in predicting susceptibility and risk to infections.
This leads us to postulate that a woman’s risk to infection and other diseases also varies over time. Developing strategies to manage these vaginal communities in ways that either promote community stability, or maintain a personalized "healthy" state, may help prevent infection and disease.
An increased awareness that the vaginal microbiome can, and does, change over time in ways that are highly personalized could reduce the misdiagnosis of vaginal dysbiosis that underlies bacterial vaginosis. This will in turn help reduce the inappropriate and unnecessary use of broad-spectrum antibiotics in misguided attempts to "restore" health.
What is the next step for your research?
The next step will involve defining the "drivers" of vaginal microbial community changes as a step toward devising strategies for vaginal ecosystem management.
Identify host factors – both genetic and behavioral – that influence the species composition and dynamics of vaginal communities.
Identify predictors of change or instability of a microbial community, and associate those with increased risk to diseases. These could be certain types of bacteria and their genomic features. These genomic features could become excellent predictive biomarkers.
It is important to note that the detailed information from this study is the first step in understanding the role of vaginal microbiota in health and disease. We have established a very important baseline in healthy women. We are now familiar with vaginal microbial communities, and how their presence and abundance” changes over time. A missing link in characterizing the healthy vaginal microbiota is a better understanding of the functional interactions between vaginal microbes and the host (and/or pathogens) (i.e., what are they doing?), and studies are underway to accomplish this by transcriptional profiling and metabolome analyses.
These are Xia Zhou, M.D.'s written remarks. Please refer to the video interview for exact quotes.
Related Research Papers
Temporal Dynamics of the Human Vaginal Microbiota
Press release: Rethinking a "healthy" vagina