Association of high-risk sexual behaviour with diversity of the vaginal microbiota and abundance of Lactobacillus

PLoS One. 2017 Nov 2;12(11):e0187612. doi: 10.1371/journal.pone.0187612. eCollection 2017.


Objective: To compare the vaginal microbiota of women engaged in high-risk sexual behaviour (sex work) with women who are not engaged in high-risk sexual behaviour. Diverse vaginal microbiota, low in Lactobacillus species, like those in bacterial vaginosis (BV), are associated with increased prevalence of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) acquisition. Although high-risk sexual behaviour increases risk for STIs, the vaginal microbiota of sex workers is understudied.

Methods: A retrospective cross-sectional study was conducted comparing vaginal microbiota of women who are not engaged in sex work (non-sex worker controls, NSW, N = 19) and women engaged in sex work (female sex workers, FSW, N = 48), using Illumina sequencing (16S rRNA, V3 region).

Results: Bacterial richness and diversity were significantly less in controls, than FSW. Controls were more likely to have Lactobacillus as the most abundant genus (58% vs. 17%; P = 0.002) and composition of their vaginal microbiota differed from FSW (PERMANOVA, P = 0.001). Six microbiota clusters were detected, including a high diversity cluster with three sub-clusters, and 55% of women with low Nugent Scores fell within this cluster. High diversity was observed by 16S sequencing in FSW, regardless of Nugent Scores, suggesting that Nugent Score may not be capable of capturing the diversity present in the FSW vaginal microbiota.

Conclusions: High-risk sexual behaviour is associated with diversity of the vaginal microbiota and lack of Lactobacillus. These factors could contribute to increased risk of STIs and HIV in women engaged in high-risk sexual behaviour.

MeSH terms

  • Female
  • Humans
  • Lactobacillus / isolation & purification*
  • Microbiota*
  • Sexual Behavior*
  • Vagina / microbiology*

Grant support

This research was supported by a Team Grant on Mucosal Immunology for HIV Vaccine Development [FRN#138657] from the Canadian Institutes of Health Research (CIHR) (CK), and CIHR Operating Grants [MOP #86721, OCH #126275] (KF) and [S5 386-01] from Grand Challenges Canada (JL). CK is a recipient of an Applied HIV Research Chair Award from the Ontario HIV Treatment Network (OHTN). Salary support was provided by the Ontario Women’s Health Scholars Award which is funded by the Ministry of Health and Long Term Care (JMW) and Ontario Graduate Scholarship (DV). The funding bodies had no role in study design, collection, analysis, or interpretation of data.