Vaginal microbiome of reproductive-age women.

The means by which vaginal microbiomes help prevent urogenital diseases in women and maintain health are poorly understood. To gain insight into this, the vaginal bacterial communities of 396 asymptomatic North American women who represented four ethnic groups (white, black, Hispanic, and Asian) were sampled and the species composition characterized by pyrosequencing of barcoded 16S rRNA genes. The communities clustered into five groups: four were dominated by Lactobacillus iners, L. crispatus, L. gasseri, or L. jensenii, whereas the fifth had lower proportions of lactic acid bacteria and higher proportions of strictly anaerobic organisms, indicating that a potential key ecological function, the production of lactic acid, seems to be conserved in all communities. The proportions of each community group varied among the four ethnic groups, and these differences were statistically significant [χ(2)(10) = 36.8, P < 0.0001]. Moreover, the vaginal pH of women in different ethnic groups also differed and was higher in Hispanic (pH 5.0 ± 0.59) and black (pH 4.7 ± 1.04) women as compared with Asian (pH 4.4 ± 0.59) and white (pH 4.2 ± 0.3) women. Phylotypes with correlated relative abundances were found in all communities, and these patterns were associated with either high or low Nugent scores, which are used as a factor for the diagnosis of bacterial vaginosis. The inherent differences within and between women in different ethnic groups strongly argues for a more refined definition of the kinds of bacterial communities normally found in healthy women and the need to appreciate differences between individuals so they can be taken into account in risk assessment and disease diagnosis.

Comparison of self-collected and physician-collected vaginal swabs for microbiome analysis.

To our knowledge, no data are available on whether the microbial species composition and abundance sampled with self-collected vaginal swabs are comparable to those of swabs collected by clinicians. Twenty healthy women were recruited to the study during a routine gynecological visit. Eligible women were between 18 and 40 years old with regular menstrual cycles. Participants self-collected a vaginal swab using a standardized protocol and then were examined by a physician, who collected an additional five swabs from the lateral wall of the mid-vagina. In this study, the self-collected and three physician-obtained swabs were analyzed and compared using terminal restriction fragment length polymorphism and sequence analyses of the 16S rRNA genes. Vaginal microbial community comparative statistical analyses of both T-RFLP and 16S rRNA gene sequence datasets revealed that self-collected vaginal swabs sampled the same microbial diversity as physician collected swabs of the mid-vagina. These findings enable large-scale, field-based studies of the vaginal microbiome.