Vaginal Microbiota Profile Predictive of Chlamydia Susceptibility

Vaginal microbiota dominated by L iners has been shown to exhibit rapid change in composition in and out of community states similar to bacterial vaginosis.

Vaginal microbiota were shown to be primarily dominated by Lactobacillus crispatus and L iners, the latter of which was associated with an increased risk for Chlamydia trachomatis infection, according to the results of a recent study published in Sexually Transmitted Infections.

In this nested case-control study, data from yearly population-based screening for C trachomatis were used to compare vaginal microbiota from Dutch women who tested negative at one screening and positive at the following screening with controls who tested negative at 2 yearly screenings in a row. Vaginal swabs from the first visit were analyzed using 16s rRNA sequencing.

Of the 5 vaginal community state types identified, 4 were predominated by Lactobacillus species: L crispatus (37%), L iners (33%), L gasseri (3%), and L jensenii (2%). The fifth community state type (25%) was comprised of various strict and facultative anaerobic bacteria, including Gardnerella vaginalis, Megasphaera spp., Atopobium vaginae, and Prevotella spp.

A vaginal community state type dominated by L iners was associated with an increased risk for C trachomatis infection within one year of sampling (odds ratio [OR] 2.58; 95% CI, 1.01-6.61). Another factor associated with acquisition of C trachomatis was being in a sexual relationship but living apart (OR 14.51; 95% CI, 1.45-145.3).

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In a linear discriminant analysis effect size algorithm, C trachomatis infection acquisition was strongly associated with the presence of L iners and P amnii. In contrast, not acquiring C trachomatis was associated with the presence of L crispatus.

The study authors explained that “vaginal microbiota dominated by Lactobacillus spp. does not necessarily protect against the acquisition of [sexually transmitted infections] like C trachomatis.” Based on these results, the authors suggested that “the composition of the vaginal microbiota is indicative of increased host predisposition to acquiring [sexually transmitted infections]. The exact mechanism behind this still needs to be unraveled.”


van Houdt R, Ma B, Bruisten SM, Speksnijder AGCL, Ravel J, de Vries HJC. Lactobacillus iners-dominated vaginal microbiota is associated with increased susceptibility to Chlamydia trachomatis infection in Dutch women: a case-control study [published online September 25, 2017]. Sex Transm Infect. doi: 10.1136/sextrans-2017-053133