Utilization of molecular methods to identify prognostic markers for recurrent bacterial vaginosis

• We performed a longitudinal study of recurrent bacterial vaginosis (BV).
• BVAB2 and Megasphaera at initial diagnosis were associated with recurrent BV.
• Gardnerella vaginalis concentration post-treatment was associated with recurrent BV.
• Molecular analysis may be useful to evaluate risk for recurrent BV.

BackgroundRecurrent bacterial vaginosis (BV) after antimicrobial therapy is a major problem, affecting >50% of patients within 1 year. The objective of this study was to determine if prospective identification of patients at risk for recurrence using molecular methods is feasible.MethodsWomen were evaluated for BV by Amsel criteria and Nugent score. Vaginal specimens were analyzed using a panel of quantitative real-time polymerase chain reactions (qPCRs) at three times: pre-treatment, 7–10 days post-treatment and 40–45 days post-treatment. The PCRs quantified DNA of the following organisms: Gardnerella vaginalis; Atopobium vaginae; Bacterial Vaginosis–Associated Bacteria-1 (BVAB1), -2 (BVAB2) and -3 (BVAB3); Leptotrichia/Sneathia; Megasphaera Phylotypes 1 and 2; and Lactobacillus spp. (L. crispatus, L. gasseri, L. iners and L. jensenii).ResultsOut of 84 women diagnosed with BV (Amsel ≥3 and Nugent ≥4), 77 (91.7%) were successfully treated after 7-10 days (asymptomatic and Amsel of either 0 or 1 with elevated vaginal pH and Nugent ≤6). Of these 77 women, 46 (59.7%) remained cured after 40–45 days and 31 (40.3%) developed recurrent BV. In univariate analysis, we found that women who would have recurrent BV during the study had greater concentrations of Megasphaera Phylotype 2 (P = 0.001) and BVAB2 (P = 0.015) at initial diagnosis and greater vaginal pH (P = 0.030), higher Nugent score (P = 0.043) and a greater concentration of G. vaginalis (P = 0.012) post-treatment, when compared to women who were cured during the study. These differences largely remained when cure was defined as Nugent ≤3 or when only women treated with intravaginal metronidazole were evaluated.ConclusionMolecular analysis of BV is a useful adjunct to clinical and microscopic analysis to prospectively identify patients at high risk for recurrent BV.