Bacterial Vaginosis and Spontaneous Clearance of Chlamydia trachomatis in the Longitudinal Study of Vaginal Flora

Abstract

Background Up to 26% of urogenital Chlamydia trachomatis infections spontaneously resolve between detection and treatment. Mechanisms governing natural resolution are unknown. We examined whether bacterial vaginosis (BV) was associated with greater chlamydia persistence versus spontaneous clearance in a large, longitudinal study. Methods Between 1999-2003, the Longitudinal Study of Vaginal Flora followed reproductive-age women quarterly for one year. Baseline chlamydia screening and treatment were initiated after ligase chain reaction testing became available mid-study, and unscreened endocervical samples were tested after study completion. Chlamydia clearance and persistence were defined between consecutive visits without chlamydia-active antibiotics (N = 320 persistence/N = 310 clearance). Associations between Nugent score (0-3, no BV; 4-10, intermediate/BV), Amsel-BV, and chlamydia persistence versus clearance were modeled with alternating and conditional logistic regression. Results 48% of chlamydia cases spontaneously cleared by the next visit (310/630). Nugent-Intermediate/BV was associated with higher odds of chlamydia persistence (aOR = 1.89, 95% CI:1.30-2.74), and the findings were similar for Amsel-BV (aOR 1.39, 95% CI:0.99-1.96). The association between Nugent-Intermediate/BV and chlamydia persistence was stronger in a within-participant analysis of 67 participants with both clearance/persistence intervals (aOR = 4.77, 95% CI:1.39-16.35). BV symptoms did not affect any results. Conclusions BV is associated with greater chlamydia persistence. Optimizing the vaginal microbiome may promote chlamydia clearance.

Association of Chlamydia trachomatis burden with the vaginal microbiota, bacterial vaginosis, and metronidazole treatment

“…Clearly, the interactions between the genital microbiota and Ct are more complex to evaluate than originally anticipated. However, a new model may be emerging from ours and others recent data ( Geisler et al., 2008 ; Geisler et al., 2013 ; Mott et al., 2021 ; Brown et al., 2023 ; Jordan et al., 2023 ), and our rapidly increasing understanding of the microbiota at this unique site. First, given the maintenance of tryptophan synthase in nearly all genital Ct isolates, there is little reason to doubt that the net presence of indole is an important mechanism for Ct escape ( Caldwell et al., 2003 ; Nelson et al., 2005 ; Ziklo et al., 2016 ; Sherchand and Aiyar, 2019 ; Mott et al., 2021 ).…”

“…How BV modulates the host-Ct relationship is not fully understood, but it is known that some BV-associated bacteria (BVAB) synthesize indole, a compound which is hypothesized to be utilized by Ct to interfere with interferon gamma (IFNγ)-mediated immunity ( Caldwell et al., 2003 ; Aiyar et al., 2014 ). Recently, an elevated Nugent score, inclusive of both intermediate microbiota and BV, was reported to be associated with greater chlamydial persistence ( Brown et al., 2023 ), suggesting that disruption of an optimal vaginal microbiota may interfere with Ct clearance. We have also reported that successful metronidazole (MTZ) treatment of BV in Ct-infected women was more likely to permit natural, spontaneous Ct clearance compared to MTZ treatment that failed to resolve BV ( Mott et al., 2021 ).…”

Vaginal microbiota transplantation is a truly opulent and promising edge: fully grasp its potential

“…The bacterial diversity in the vaginal microbiota is comparatively lower than that found in the intestinal tract. The vaginal environment is primarily regulated by a diverse range of lactic acid bacteria to maintain homeostasis (Brown et al, 2023). However, the vaginal environment in an individual's life is dynamic and presents complex circumstances.…”