Abstract
Vaginal dysbiosis has been shown to increase the risk of some adverse birth outcomes. HIV infection may be associated with shifts in the vaginal microbiome. We characterized microbial communities in vaginal swabs collected between 16–20 gestational weeks in the Zambian Preterm Birth Prevention Study to investigate whether HIV and its treatment alter the microbiome in pregnancy. We quantified relative abundance and diversity of bacterial taxa by whole-genome shotgun sequencing and identified community state types (CST) by hierarchical clustering. Associations between exposures—HIV serostatus (HIV+ vs HIV-) and preconceptional ART (ART+ vs ART-)—and microbiome characteristics were tested with rank-sum, and by linear and logistic regression, accounting for sampling by inverse-probability weighting. Of 261 vaginal swabs, 256 (98%) had evaluable sequences; 98 (38%) were from HIV+ participants, 55 (56%) of whom had preconceptional ART exposure. Major CSTs were dominated by: L. crispatus (CST 1; 17%), L.] iners (CST 3; 32%), Gardnerella vaginalis (CST 4-I; 37%), G. vaginalis & Atopobium vaginae (CST 4-II; 5%), and other mixed anaerobes (CST 4-III; 9%). G. vaginalis was present in 95%; mean relative abundance was higher in HIV+ (0.46±0.29) compared to HIV- participants (0.35±0.33; rank-sum p = .01). Shannon diversity was higher in HIV+/ART+ (coeff 0.17; 95%CI (0.01,0.33), p = .04) and HIV+/ART- (coeff 0.37; 95%CI (0.19,0.55), p < .001) participants compared to HIV-. Anaerobe-dominant CSTs were more prevalent in HIV+/ART+ (63%, AOR 3.11; 95%CI: 1.48,6.55, p = .003) and HIV+/ART- (85%, AOR 7.59; 95%CI (2.80,20.6), p < .001) compared to HIV- (45%). Restricting the comparison to 111 women in either CST 3 (L. iners dominance) or CST 1 (L. crispatus dominance), CST 3 frequency was similar in HIV- (63%) and HIV+/ART- participants (67%, AOR 1.31; 95%CI: (0.25,6.90), p = .7), but higher in HIV+/ART+ (89%, AOR 6.44; 95%CI: (1.12,37.0), p = .04). Pregnant women in Zambia, particularly those with HIV, had diverse anaerobe-dominant vaginal microbiota.
Highlights
The vaginal microbial environment plays an important role in sexual and reproductive health outcomes
In contrast to the gut, where low microbial diversity is associated with disease, most vaginal microbial communities defined in Western studies are dominated by one of four aerobic Lactobacillus species: L. crispatus (Community State Type [CST] 1), L. gasseri (CST 2), L. iners (CST 3), or L. jensenii (CST 5).[1]
Vaginal microbiota dominated by anaerobes and devoid of Lactobacillus have been associated with adverse birth outcomes such as preterm birth (PTB).[10, 11]
Summary
The vaginal microbial environment plays an important role in sexual and reproductive health outcomes. In contrast to the gut, where low microbial diversity is associated with disease, most vaginal microbial communities defined in Western studies are dominated by one of four aerobic Lactobacillus species: L. crispatus (Community State Type [CST] 1), L. gasseri (CST 2), L. iners (CST 3), or L. jensenii (CST 5).[1] Another community state type (CST 4), characterized by predominance of anaerobic species like Gardnerella vaginalis and other bacteria implicated in clinical bacterial vaginosis, has been linked to increased susceptibility to sexually transmitted infections and HIV,[2, 3] perioperative and peripartum pelvic infections,[4, 5] and infertility.[6] Anaerobe species can disturb the vaginal epithelial barrier integrity, incite an inflammatory response, and impede wound healing.[7, 8] relative abundance of Lactobacillus species in the vagina causes increased production of lactic acid and low pH, which is protective against a range of infections.[9]. The biological mechanism(s) linking the virus and its treatment to PTB remain poorly understood
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
