(P267-LB) Associations of the vaginal microbiome with HIV status and STI diagnosis during pregnancy and the postpartum period in South African women

Wednesday, July 26, 2023

16:00 – 18:00 CST

Primary Presenter(s)

Katherine Li, MD (she/her/hers)

Clinical infectious disease fellow
University of California Los Angeles
Los Angeles, California, United States

Co-author(s)

FL

Fan Li

Department of Pediatric Infectious Diseases, David Geffen School of Medicine, University of California Los Angeles, United States
HJ

Heather Jaspan

Seattle Children’s’ Research Institute, University of Washington
Seattle, Washington, United States
DN

Dorothy C. Nyemba, n/a

Ms
University of Cape Town
Cape Town, Western Cape, South Africa
LM

Landon Myer

University of Cape Town, United States
DJ

Dvora Joseph Davey

Division of Infectious Disease, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA, United States

Background: Pregnant women in Sub-Saharan Africa have high prevalence of sexually transmitted infections (STIs) including HIV. African women have more diverse vaginal microbiota than women of European descent, and there is interest in the impact of this diversity on HIV and STI acquisition.

Methods: We followed women ≥18 years with and without HIV over two visits during pregnancy and one visit postpartum. At each visit we obtained HIV testing and self-collected vaginal swabs for point of care testing for C. trachomatis, N. gonorrhea, and T. vaginalis (Cepheid GeneXpert) and microbiome sequencing of the V4(515F/806R) region of the 16S rRNA gene. We categorized microbial communities using VALENCIA nearest-centroid classification and evaluated associations with HIV status and STI diagnosis at each visit using mixed-effect linear models.

Results: Across 242 women (mean age 29, 44% living with HIV), 33% were diagnosed with STIs. 22% were diagnosed with C. trachomatis, 6% with N. gonorrhea, and 16% with T. vaginalis. We identified four main community state types (CSTs): two lactobacillus-dominated CSTs (CST I dominated by Lactobacillus crispatus, CST III by Lactobacillus iners) and two anaerobe-dominant CSTs (CST IV-AB dominated by Gardnerella vaginalis, and CST IV-C by highly diverse facultative anaerobes). Microbial composition differed by baseline HIV status (PERMANOVA R²=0.002, p=0.006) and by STI diagnosis (PERMANOVA R²=0.002, p=0.004). Shannon diversity was increased in women who had an STI diagnosis (p = 0.004). At first antenatal visit, women diagnosed with any STI were more likely to have microbiomes categorized as CST III (dominated by Lactobacillus iners) and CST IV-AB (dominated by Gardnerella vaginalis, Fisher’s exact p = 0.013). Postpartum, women with any STI diagnosis to be more likely to have microbiomes categorized as CST IV-C (dominated by diverse facultative anaerobes, p = 0.07). Individual species associated with STI diagnosis included Prevotella species, Metamycoplasma hominis and Sneathia amnii

Conclusion: In pregnant South African women, diagnosis of an STI is associated with more anaerobe-dominant vaginal microbiome composition, and specifically with increased Prevotella species as well as Metamycoplasma hominis and Sneathia amnii. More work is needed to understand how the vaginal microbiome modulates risk of HIV and STI acquisition.