2574. Temporal Changes in the Vaginal Microbiome During Treatment for Bacterial Vaginosis: Is Lactobacillus Iners an Important Player?

BACKGROUND: Bacterial vaginosis (BV) is the most common vaginal condition affecting women of reproductive age and yet it remains poorly understood. Recurrent BV causes significant emotional and psychological distress and can prove difficult to resolve with currently available treatments. We aimed to investigate the microbiome of recurrent BV patients at various time points in relation to oral Metronidazole treatment. METHODS: Women aged 18–40 years, with recurrent BV, were prospectively enrolled. Vaginal samples (lavage) were collected at baseline (D0), at 7–10 days (D7) and 30–40 days (D30) after initiation of oral metronidazole treatment (500 mg BID, 7 days). DNA was extracted, amplified using primers targeting the V3-V4 region of the 16 srRNA, and then sequenced and processed through a hybrid Qiime MICCA bioinformatics pipeline. RESULTS: Seventeen recurrent BV patients were enrolled. Alpha diversity decreased (P = 0.0049) after the first week of treatment with oral metronidazole, but increased (P = 0.0062) to near baseline by D30. Lactobacillus iners, was the dominant Lactobacillus, with transient increase in this species corresponding with metronidazole treatment. There was also a decrease in Gardnerella vaginalis that re-normalized to baseline at 30 days. Of the 10 recurrent BV patients with data for all three time points, 4 relapsed by D30. Β diversity differed significantly between patients that relapsed and those that did not (p = 0.044). Alpha diversity did not differ between the groups (p = 0.07). CONCLUSION: The dominant Lactobacillus pretreatment in this cohort was L.iners. Oral metronidazole was associated with a decrease in alpha diversity, decrease in G. vaginalis and increase in L. iners. Although L. iners increased after metronidazole treatment, this increase was not sustained by D30. Treatment with metronidazole, only temporarily altered the microbiome. Further studies are needed to clarify the role of L. iners in recurrent BV. [Image: see text] DISCLOSURES: All authors: No reported disclosures.