A33 The cervico-vaginale microbiota in chlamydia trachomtais notified women: a case–control study at the sexually transmitted infection outpatient clinic in Amsterdam

Increasing evidence suggests that the cervico-vaginal microbiome (CVM) plays an important role in acquiring sexually transmitted infections (STIs). Here we studied the CVM in women exposed to Chlamydia trachomatis (Ct). We included 98 women who were notified by Ct-positive sex partners via contact-tracing at the STI outpatient clinic in Amsterdam, the Netherlands. Cervico-vaginal samples and clinical data were collected for all women. CVM compositions were characterized by sequencing of the V3/V4 region of the 16srRNA gene using the Illumina MiSeq platform. High quality reads were assigned to operational taxonomic units and classified using a vaginal reference package. Hierarchical clustering delineated CVM clusters based on microbial relative abundances. Possible determinants for acquiring Ct were analyzed using multivariable logistic regression. The CVM was characterized for 93 women, of whom 52 were Ct positive and 41 Ct negative. We identified three major CVM clusters. Clustered CVM predominantly comprised either diverse anaerobic bacteria (n = 39; 42%), Lactobacillus iners (n = 32; 34%) or Lactobacillus crispatus (n = 22; 24%). In multivariable analysis, we found that the CVM was significantly associated with C. trachomatis infection (OR = 4.2 (95% confidence interval, CI: 1.2–15.4) for women with diverse anaerobic CVM and OR = 4.4 (CI: 1.3–15.6), for women with L. iners-dominated CVM, compared to women with L. crispatus-dominated CVM), as was younger age (OR = 3.1, CI: 1.1–8.7, for those ≤21 years old) and reporting a steady sex partner (OR = 3.6, CI: 1.4–9.4). Women who tested positive for Chlamydia trachomatis infection after having been contact-traced by a chlamydia positive partner were more likely to have CVM dominated by L. iners or by diverse anaerobic bacteria, than by L. crispatus.