Polymicrobial Gardnerella biofilm resists repeated intravaginal antiseptic treatment in a subset of women with bacterial vaginosis: a preliminary report

Purpose: Bacterial vaginosis is a recalcitrant polymicrobial biofilm infection that often resists standard antibiotic treatment. We therefore considered repeated treatment with octenidine, a local antiseptic that has previously been shown to be highly effective in several biofilm-associated infections. Methods: Twenty-four patients with recurrent BV were treated with a 7-day course of octenidine (octenidine dihydrochloride spray application with the commercial product Octenisept). In case of treatment failure or relapse within 6 months, patients were re-treated with a 28-day course of octenidine. In case of recurrence within 6 months after the second treatment course, patients were treated again with a 28-day course followed by weekly applications for 2 months. Treatment effect was evaluated by assessment of the presence of the biofilm on voided vaginal epithelial cells through fluorescence in situ hybridisation. Results: The initial cure rate following a 7-day course of octenidine was as high as 87.5 %. The 6-month relapse rate was, however, as high as 66.6 %. Repeated treatment for 28 days led to an overall cure rate of 75.0 %; however, it was also associated with emergence of complete resistance to octenidine in a subset of women. The overall cure rate after three treatment courses with 1-year follow-up was 62.5 %, with 37.5 % of the patients showing complete resistance to octenidine. Conclusion: Our preliminary results showed that octenidine dihydrochloride was initially highly effective, but the efficacy of repeated and prolonged treatment dropped quickly as challenge with the antiseptic rapidly led to bacterial resistance in a considerable subset of women