Description
Sexual behaviours impact the vaginal microbiota of women who have sex with women
Plummer EL1, Vodstrcil LA1,2, Murray GL3, Tabrizi SN3, Garland SM3, Fairley CK1, Tan A3, Law M4, Hocking JS2, Bulach DM5, Philip G5, Bradshaw CS1,2
1Central Clinical School, Monash University; Melbourne Sexual Health Centre, Alfred Health; 2Melbourne School of Population & Global Health, The University of Melbourne; 3The Royal Women's Hospital; 4Kirby Institute, UNSW Australia; 5Melbourne Bioinformatics, The University of Melbourne
We investigated the impact of sexual behaviors on the vaginal microbiota (VM) of women-who-have-sex-with-women (WSW) participating in a 2 year cohort study. Women self-collected high vaginal swabs and completed a behavioral questionnaire every 3 months for 24 months or until incident bacterial vaginosis (BV). We characterized the VM using 16S-rRNA gene sequencing of the V3V4 region. Community state types (CSTs) were identified using hierarchical clustering. Bacterial diversity was calculated using the Shannon diversity index and instability of the VM was assessed using change of CST and Bray-Curtis dissimilarity between consecutive longitudinal specimens. The impact of behaviors on diversity and instability of the VM was determined using multivariate regression models. Linear discriminant analysis effect size was used to identify bacteria associated with exposure to a new sexual partner. 360 specimens from 100 women were included in analyses. The VM clustered into 5 CSTs: 3 dominated by Lactobacillus spp. (CST1 L. crispatus; CST2 L. crispatus and L. iners; CST3 L. iners), one abundant in Gardnerella vaginalis and one of mixed bacteria. Exposure to a new sexual partner increased bacterial diversity (Adj coef=0.33,95%CI:0.11,0.54) and instability of the VM, both in terms of change of CST (AOR=2.69,95%CI:1.37,5.28) and increased Bray-Curtis dissimilarity (Adj coef=0.22,95%CI:0.12,0.32). Sex with a new partner increased the abundance of bacteria often seen in BV including G. vaginalis, Megasphaera and BVAB1 (p<0.05). Conversely, no sex/sex in established ongoing relationships was associated with a favorable vaginal microbiota abundant in L. crispatus. Sex with a new partner markedly reshapes the VM of WSW by increasing the diversity and abundance of potentially pathogenic bacteria.
Funding: National Health and Medical Research Council (NHMRC) Program Grant #1071269 and NHMRC Project Grant #1020457