Associations between Vaginal Microbiota and Cervicitis

Cervicitis is defined as the inflammation of the cervix. Many cases of cervicitis are caused by sexually transmitted infections (STIs); however, a substantial portion of cervicitis cases have no known etiology. Cervicitis is also known to be associated with bacterial vaginosis (BV), a clinical condition characterized by the transition of the vaginal microbiota from being Lactobacilli dominated to having higher bacterial diversity. In this analysis, we investigated the relationship between specific vaginal bacterial species and cervicitis. Methods: For this cross-sectional analysis, we utilized data from participants in the placebo arm of the Preventing Vaginal Infections trial. During bimonthly pelvic exams, cervicovaginal swabs were collected, and quantitative polymerase chain reaction assays were used to measure the concentrations of specific taxa. For the exposure, concentrations for each bacterial taxon were categorized into tertiles; samples with concentrations below the lower limit of quantitation were classified as not detectable and served as the reference group. Cervicitis was defined as having 30 or more polymorphonuclear leukocytes per high power field on microscopy on cervical Gram stain. We used Poisson GEE models to evaluate the association between bacterial concentration, categorized as tertiles, and cervicitis prevalence and estimate prevalence ratios. Results: In the analysis adjusting for sexually transmitted infections, vaginal washing, and condom use, certain BV-associated bacteria had one or more tertiles that were associated with an increased detection of cervicitis, including BVAB1, Megasphaera species, and Mageeibacilus indolicus. Only the highest tertiles of Lactobacillus iners and Lactobacillus jensenii were associated with an increased detection of cervicitis. Conclusions: Presence of certain BV-associated species and Lactobacillus species in the vagina may contribute to cervicitis. This analysis was limited to Kenya and the US, and given differences of vaginal microbiota by region, additional studies are needed to understand if these associations are present in other regions. Further study is also needed to explore the role of lactobacilli in cervicitis.