Sex Work Is Associated With Increased Vaginal Microbiome Diversity in Young Women From Mombasa, Kenya

Abstract

Background: Although nonoptimal vaginal bacteria and inflammation have been associated with increased HIV risk, the upstream drivers of these phenotypes are poorly defined in young African women. Setting: Mombasa, Kenya. Methods: We characterized vaginal microbiome and cytokine profiles of sexually active young women aged 14–24 years (n = 168) in 3 study groups: those engaging in formal sex work, in transactional sex, and nonsex workers. Vaginal secretions were collected using self-inserted SoftCup, and assayed for cytokines and vaginal microbiome through multiplex ELISA and 16S rRNA sequencing, respectively. Epidemiological data were captured using a validated questionnaire. Results: The median age of participants was 20 years (interquartile range: 18–22 years). Approximately two-thirds of young women (105/168) had vaginal microbial communities characterized by Gardnerella and/or Prevotella spp. dominance; a further 29% (49/168) were predominantly Lactobacillus iners. Microbiome clustering explained a large proportion of cytokine variation (>50% by the first 2 principal components). Age was not associated with vaginal microbial profiles in bivariable or multivariable analyses. Women self-identifying as sex workers had increased alpha (intraindividual) diversity, independent of age, recent sexual activity, HIV, and other sexually transmitted infections (beta = 0.47, 95% confidence interval: 0.05 to 0.90, P = 0.03). Recent sex (number of partners or sex acts last week, time since last vaginal sex) correlated with increased alpha diversity, particularly in participants who were not involved in sex work. Conclusion: Nonoptimal vaginal microbiomes were common in young Kenyan women and associated with sex work and recent sexual activity, but independent of age. Restoring optimal vaginal microflora may represent a useful HIV prevention strategy.

Endocervical regulatory T cells are associated with decreased genital inflammation and lower HIV target cell abundance

“…This could be an important consideration, as bacterial vaginosis, a condition marked by depletion of vaginal health associated Lactobacillus, is associated with increased risk of STI acquisition [32][33][34][35] , reproductive complications [36][37][38] , and is highly recalcitrant to existing treatments 39 , so modulating the detrimental effects of bacteria could be an alternative or additional approach to minimize the impact of BV. Similar to what we have previously shown in a cohort of adolescent girls and young women in Mombasa, Kenya 40 , our current data also indicates that involvement in sex work might be associated with non-optimal vaginal microbiomes. Most women in SWOP displayed a non-Lactobacillus microbial profile characterized predominantly by Sneathia, Prevotella, and Gardnerella.…”

“…CC-BY-NC-ND 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made broad, with sources including sexual intercourse 40 , intravaginal practices, bacterial/viral sexually transmitted infections (STIs) 44,45 , and non-Lactobacillus vaginal microbiota associated with bacterial vaginosis 46 , one advantage of inducing regulatory mechanisms to reduce inflammation is that this regulation could protect against inflammation regardless of the cause. The strongest immune associations with endocervical Treg included overall CD4+ T cell abundance, which are believed to be required for HIV to establish itself in the mucosa, and a number of cytokines including those that attract immune cells to the site.…”

Endocervical Regulatory T Cells Are Associated With Decreased Genital Inflammation and Lower HIV Target Cell Abundance

“…This could be an important consideration, as bacterial vaginosis, a condition marked by depletion of vaginal health associated Lactobacillus, is associated with increased risk of STI acquisition (32)(33)(34)(35), reproductive complications (36)(37)(38), and is highly recalcitrant to existing treatments (39), so modulating the detrimental effects of bacteria could be an alternative or additional approach to minimize the impact of BV. Similar to what we have previously shown in a cohort of adolescent girls and young women in Mombasa, Kenya (40), our current data also indicates that involvement in sex work might be associated with non-optimal vaginal microbiomes. Most women in SWOP displayed a non-Lactobacillus microbial profile characterized predominantly by Sneathia, Prevotella, and Gardnerella.…”

“…In summary, our data provide important insights into mechanisms that may be critical in regulating inflammation and its pathogenic effects. Since the causes of genital inflammation are quite broad, with sources including sexual intercourse ( 40 ), intravaginal practices, bacterial/viral sexually transmitted infections (STIs) ( 43 , 44 ), and non- Lactobacillus vaginal microbiota associated with bacterial vaginosis ( 45 ), one advantage of inducing regulatory mechanisms to reduce inflammation is that this regulation could protect against inflammation regardless of the cause. The strongest immune associations with endocervical Treg included overall CD4+ T cell abundance, which are believed to be required for HIV to establish itself in the mucosa, and a number of cytokines including those that attract immune cells to the site.…”

Gardnerella subgroup dominant microbiomes are associated with divergent cervicovaginal immune responses in a longitudinal cohort of Kenyan women

“…Here cpn 60 microbial profiling of cervicovaginal specimens was performed to describe specific microbial structures associated with changes in the local immune milieu in a low-risk longitudinal cohort. Studies to date examining mucosal immunity and microbiome/BV associations have been (with few exceptions) cross-sectional and in populations either pregnant or at high risk for sexually transmitted infections and given the impact of those conditions on mucosal immunity may not be generalizable to the general population ( 12 , 22 , 24 , 54 , 55 ). Furthermore, none of these studies employed cpn 60 barcoding or whole genome sequencing so they were unable to examine the contributions of different Gardnerella subgroups to mucosal immunity.…”