O03.2 The short-term immune impact of bacterial vaginosis treatment is unrelated to Lactobacillus spp. abundance
Year: 2021
Type: conference-abstract
Abstract: Background Bacterial vaginosis (BV) induces genital inflammation and enhances HIV acquisition risk, while vaginal Lactobacillus predominance is associated with mucosal immune quiescence and reduced HIV risk. BV treatment reduces vaginal proinflammatory cytokines, but it is unclear whether this is due to reductions in BV-associated anaerobes or an increase in Lactobacillus spp. We investigated the short-term impact of BV treatment on the vaginal immune milieu and microbiome. Methods Study participants comprised 48 women with BV, all of whom were treated with intravaginal metronidazole for 5 days before enrollment into a clinical trial of the live biotherapeutic LACTIN-V to prevent BV recurrence. Vaginal swabs were collected at baseline and within 48 hours of completing metronidazole treatment, prior to study product administration. Soluble immune factors were assayed from vaginal swabs by multiplex ELISA, relative bacterial abundance was assessed by metagenomic sequencing (NovaSeq), and absolute abundance of key bacterial species was assessed by qPCR. Results Immediately following treatment, there was a marked drop in the vaginal level of proinflammatory cytokines (IL-1a, IL-6), chemokines (IL-8, MIP-1b, MIP-3a) and a marker of epithelial barrier disruption (sE-cad; all p<0.01). The vaginal microbiome was generally shifted from BV to community state types (CSTs) dominated by L. iners (49%) or L. jensenii (31%), However, these CST shifts were driven by a dramatic (7–12-fold) reduction in the absolute abundance of BV-associated Gram negative anaerobes (Prevotella spp., Gardnerella vaginalis, Atopobium vaginae, and Megasphaera; all p<0.001), while there were minor or no increases in the absolute abundance of L. jensenii (2.9-fold increase, p=0.006) or L. iners (0.6-fold reduction, p=0.245). Conclusions Standard BV therapy reduced inflammatory cytokines/chemokines and enhanced epithelial integrity in the short term. Despite a shift to CSTs dominated by lactobacilli, these immune changes were linked to reductions in the absolute abundance of BV-associated anaerobes rather than to increased Lactobacillus abundance.
Institutions: University of Toronto, University of California, San Francisco, John H. Stroger, Jr. Hospital of Cook County, Ruth M. Rothstein CORE Center, University of California San Diego, Washington University in St. Louis, University Health Network, Toronto General Hospital Research Institute, Chan Zuckerberg Biohub San Francisco, Toronto General Hospital
Language: English
Subfield: Microbiology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: gold
OpenAlex ID: W3178819837