O02.2 The impact of concurrent partner treatment for bacterial vaginosis on the genital microbiota of heterosexual couples: a pilot study

BackgroundApproximately 40% of women receiving first-line antibiotics for bacterial vaginosis (BV) experience recurrence within 3-months. Reinfection from an untreated regular sexual partner (RSP) likely contributes to BV-recurrence. We investigated the impact of concurrent partner treatment for BV on the genital microbiota of heterosexual couples.MethodsWomen with symptomatic BV (≥3 Amsel criteria and Nugent Score[NS]=4–10) were recruited between March 2018-March 2019 with their RSP. Couples received oral metronidazole 400mg BID 7-days, and men additionally applied 2% clindamycin cream topically to penile skin BID for 7-days. Participants self-collected genital samples (women: vaginal; men: cutaneous penile, first-void urine [representing the urethra]) pre-treatment (day-0), post-treatment (day-8) and then 4-weekly until endpoint (week-12 or BV-recurrence). We characterised the genital microbiota using 16S-rRNA gene sequencing. Differential abundance testing was performed using ALDEX2. Changes in microbiota composition post-treatment were assessed using ANOSIM.ResultsData from 29 couples were analysed. Women had a high prevalence of risk factors for BV-recurrence; 79% had a history of BV, 83% had an uncircumcised RSP, all reported condomless sex during the study and 38% had an intrauterine device. Only 4/27 (15%) women completing clinical follow-up experienced BV-recurrence (≥3 Amsel criteria, NS=4–10). BV-associated bacteria, including Atopobium, Prevotella and Dialister, significantly decreased in abundance at all three genital sites immediately post-treatment (false discovery rate (FDR)-corrected p-value<0.05). BV-associated bacteria remained decreased at endpoint at all sites, but following FDR-correction this was only significant for the vaginal site. Overall, partner treatment significantly and immediately changed the composition of the female and male genital microbiota (AONISM; p-value=0.001).ConclusionIn a cohort of women at high risk for BV-recurrence, only 15% experienced recurrence within 3-months of concurrent partner treatment. Treatment reduced the abundance of BV-associated bacteria and altered the genital microbiota composition of both partners; although only changes at the vaginal site remained significant at endpoint.