Vaginal and Anal Microbiome during Chlamydia trachomatis Infections

Abstract

Background. Chlamydia trachomatis (CT) is the agent of the most common bacterial sexually transmitted infection worldwide, with a significant impact on women’s health. Despite the increasing number of studies about the vaginal microbiome in women with CT infections, information about the composition of the anal microbiome is still lacking. Here, we assessed the bacterial community profiles of vaginal and anal ecosystems associated or not with CT infection in a cohort of Caucasian young women. Methods. A total of 26 women, including 10 with a contemporary vaginal and ano-rectal CT infection, were enrolled. Composition of vaginal and anal microbiome was studied by 16S rRNA gene profiling. Co-occurrence networks of bacterial communities and metagenome metabolic functions were determined. Results. In case of CT infection, both vaginal and anal environments were characterized by a degree of dysbiosis. Indeed, the vaginal microbiome of CT-positive women were depleted in lactobacilli, with a significant increase in dysbiosis-associated bacteria (e.g., Sneathia, Parvimonas, Megasphaera), whereas the anal microbiota of CT-infected women was characterized by higher levels of Parvimonas and Pseudomonas and lower levels of Escherichia. Interestingly, the microbiome of anus and vagina had numerous bacterial taxa in common, reflecting a significant microbial ‘sharing’ between the two sites. In the vaginal environment, CT positively correlated with Ezakiella spp. while Gardnerella vaginalis co-occurred with several dysbiosis-related microbes, regardless of CT vaginal infection. The vaginal microbiome of CT-positive females exhibited a higher involvement of chorismate and aromatic amino acid biosynthesis, as well as an increase in mixed acid fermentation. Conclusions. These data could be useful to set up new diagnostic/prognostic tools, offering new perspectives for the control of chlamydial infections.

Metagenomic Shotgun Sequencing of Endocervical, Vaginal, and Rectal Samples among Fijian Women with and without Chlamydia trachomatis Reveals Disparate Microbial Populations and Function across Anatomic Sites: a Pilot Study

“…Although interrogating vaginal microbial communities is important in understanding healthy versus pathogenic microbial environments and risk for STIs, evaluating the endocervix may be more pivotal, as it is the actual site of C. trachomatis infection, not the vagina. Very few studies have examined cervical microbiomes used 16S rRNA sequencing in the presence or absence of C. trachomatis without comparison to vaginal microbiota ( 21 – 24 ). Only one study to date has evaluated the interrelationship of these microbiomes, again using 16S rRNA sequencing, with a focus on adolescents in South Africa ( 11 ).…”

“…Most of what we know about the impact of STIs on rectal microbiomes is from HIV-1 studies ( 31 – 34 ). Currently, few studies have addressed C. trachomatis infections and their effect on rectal microbiota ( 22 , 35 ).…”

First-Void Urine Microbiome in Women with Chlamydia trachomatis Infection

“…In this context, recently, many authors have focused on the correlation between CT infection and the vaginal environment [ 6 , 7 , 8 , 9 , 10 , 11 ]. Some cross-sectional studies have demonstrated that the presence of bacterial vaginosis (BV), a dysbiosis status with a depletion of lactobacilli and the predominance of other anaerobic species, increases the risk of STI acquisition, including genital CT infections [ 6 , 7 , 8 ].…”

“…In this context, recently, many authors have focused on the correlation between CT infection and the vaginal environment [ 6 , 7 , 8 , 9 , 10 , 11 ]. Some cross-sectional studies have demonstrated that the presence of bacterial vaginosis (BV), a dysbiosis status with a depletion of lactobacilli and the predominance of other anaerobic species, increases the risk of STI acquisition, including genital CT infections [ 6 , 7 , 8 ]. Indeed, the vaginal environment of CT-infected women is usually characterized by a decrease in Lactobacillus spp., together with a significant increase in dysbiosis-associated bacterial taxa, such as Megasphaera spp., Atopobium vaginae , Gardnerella vaginalis , and Prevotella spp., creating a highly complex, polymicrobial community [ 12 , 13 , 14 ].…”

Towards a Deeper Understanding of Chlamydia trachomatis Pathogenetic Mechanisms: Editorial to the Special Issue “Chlamydia trachomatis Pathogenicity and Disease”

“…In this regard, several in silico approaches have been proposed, such as, for example, PICRUSt, the compound prediction of MIMOSA, MelonnPan and others, that can, indeed, provide valuable information on the metabolic potential of a given microbial community and identify the microbial taxa most likely responsible for the synthesis and/or consumption of key metabolites [ 12 ]. An example of their application came from Raimondi et al (2021), where the researchers observed, in the cervico-vaginal environment of C. trachomatis -positive patients, a higher involvement of the biosynthesis of chorismate, [ 13 ], a precursor of indole and, hence, of tryptophan, recognized as a fundamental component for the growth and pathogenesis of C. trachomatis .…”