The microbiota of aerobic vaginitis. The microbiota of aerobic vaginitis

While bacterial vaginosis (BV) is a well-known type of vaginal dysbiosis, aerobic vaginitis (AV) is an inflammatory condition, which remains understudied and often misdiagnosed. It predisposes women to serious complications including urogenital infections and pregnancy complications. Here we investigated the bacterial community in AV, aiming to find indications of its possible role in AV pathogenesis. We collected cervicovaginal lavage fluid samples of women (n=58) classified by wet mount microscopy as suffering from AV or BV, or without signs of AV or BV (reference group of asymptomatic women). Although AV samples showed reduced abundances of bacteria in general and specifically of lactobacilli in qPCR, 16S rRNA gene sequencing and amplicon sequence variant analysis revealed some samples still showed Lactobacillus as most dominant taxon. Other AV samples indicated high relative abundances of Streptococcus agalactiae and unexpectedly Prevotella bivia. The latter, commonly associated with BV, was mostly found in severe AV samples. Yet, despite being enriched in these potential pathobionts, the bacterial communities in the AV samples only slightly stimulated Toll-like receptor 4 and showed reduced activation of Toll-like receptor 2 and 6, receptors of two pathways central to mucosal immunity. Despite possible roles for the found pathobionts in the associated complications of AV, our findings suggest that host features, such as the inflammatory response, are essential to take into consideration for diagnosis and treatment of AV. They also point towards the need for strategies to boost the number of beneficial and immunomodulatory vaginal lactobacilli in AV patients.