O-277 Exploring the relationship between the vaginal microbiota and vaginal symptoms

Abstract Study question What is the relationship between self-reported vaginal symptoms and the composition of the vaginal microbiome? Summary answer Our study reveals a complex and multifactorial relationship between vaginal symptoms and the composition of the vaginal microbiome. What is known already Vaginal dysbiosis (VD) is a microbial condition characterized by the absence of beneficial lactobacilli and the presence of pathogenic bacteria in the vagina. VD is associated with elevated risks of sexually transmitted infections, preterm birth, pregnancy loss, infertility, and suboptimal outcomes in in vitro fertilization. Clinical manifestations often include increased vaginal discharge and malodour, although it’s noteworthy that a substantial proportion of women with VD remain asymptomatic, which makes diagnosing these women challenging. Study design, size, duration Our study was conducted as part of a Double-Blinded Randomized Controlled Trial (RCT) evaluating Vaginal Microbiota Transplantation (VMT) as a novel approach for treating vaginal dysbiosis without antibiotics. This study included 263 women aged 18-40 years. Participants/materials, setting, methods We employed shotgun metagenomic sequencing to analyse the vaginal microbiome on cycle day 10+/-2 days. Moreover, we collected data on vaginal symptoms, hormonal contraceptive use, and sexual behaviour. Main results and the role of chance Among the 263 participants, 65% exhibited eubiotic microbiomes, 23% had dysbiotic microbiomes, and 12% had intermediate microbiomes. Vaginal symptoms were reported by 33%, while 63% remained symptom-free. In terms of dominance, L. crispatus dominated in 40% of samples, followed by L. iners (30%) and G. vaginalis (9.1%). In symptomatic women, L. iners (22%) and L. crispatus (21%) were common taxa, while asymptomatic women showed higher prevalence of these taxa: L. crispatus (50%) and L. iners (34%). Symptoms analysis showed two significant clusters dominated by L. crispatus or L. iners, along with smaller dysbiotic clusters led by G. vaginalis and F. vaginae. Dysbiotic samples exhibited higher rates of increased discharge and malodor, while stinging and itching were more prevalent in eubiotic samples. Positive associations were noted between specific microbial taxa and distinct symptoms. Exploring external factors, contraceptive use revealed weak associations with microbial changes. Sexual behavior patterns also influenced microbial composition, notably in women with varying numbers of male sexual partners within the last 3 months. These findings provide valuable insights into the intricate interactions between vaginal microbiota, symptoms, and external factors, shedding light on the complex landscape of vaginal dysbiosis. Limitations, reasons for caution Our study is limited by the cross-sectional design, and causality cannot be inferred. Self-reporting of symptoms may introduce bias. Additionally, our findings may not be generalizable to all populations sin the majority of the women in our cohort are younger and likely to have higher education Wider implications of the findings Our findings highlight the complexity of VD symptomatology and underscore the need for further research into the relationship between vaginal symptoms, microbiota and clinical outcomes. Trial registration number NCT04855006