Treatment of biofilms in bacterial vaginosis by an amphoteric tenside pessary-clinical study and microbiota analysis

Abstract

Background: Bacterial vaginosis (BV) is the most common vaginal syndrome among women in their reproductive years. It is associated with an increased risk of acquiring sexually transmitted infections and complications like preterm labor. BV is characterized by a high recurrence rate for which biofilms frequently found on vaginal epithelial cells may be a reason.

Results: Here, we report a controlled randomized clinical trial that tested the safety and effectiveness of a newly developed pessary containing an amphoteric tenside (WO3191) to disrupt biofilms after metronidazole treatment of BV. Pessaries containing lactic acid were provided to the control group, and microbial community composition was determined via Illumina sequencing of the V1-V2 region of the 16S rRNA gene. The most common community state type (CST) in healthy women was characterized by Lactobacillus crispatus. In BV, diversity was high with communities dominated by either Lactobacillus iners, Prevotella bivia, Sneathia amnii, or Prevotella amnii. Women with BV and proven biofilms had an increased abundance of Sneathia sanguinegens and a decreased abundance of Gardnerella vaginalis. Following metronidazole treatment, clinical symptoms cleared, Nugent score shifted to Lactobacillus dominance, biofilms disappeared, and diversity (Shannon index) was reduced in most women. Most of the patients responding to therapy exhibited a L. iners CST. Treatment with WO 3191 reduced biofilms but did not prevent recurrence. Women with high diversity after antibiotic treatment were more likely to develop recurrence.

Conclusions: Stabilizing the low diversity healthy flora by promoting growth of health-associated Lactobacillus sp. such as L. crispatus may be beneficial for long-term female health.

Trial registration: ClinicalTrials.gov NCT02687789.

Keywords: Amphoteric tenside; Bacterial vaginosis; Biofilms; Vaginal microbiome; Vaginal microbiota.

Conflict of interest statement

Ethics approval and consent to participate

The study protocol was approved by the local ethics committee (Bayerische Landesärtzekammer, München) and written consent was obtained from all participants. This study was conducted in accordance with the Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects. Principles and guidelines for good clinical practice were followed.

Competing interests

The authors have read the journal’s policy. CA and CM have the following competing interests: They work for the company Dr. August Wolff GmbH & Co. KG Arzneimittel which designed and conducted the clinical study. However, they had no influence on data analysis and interpretation, or the decision to submit the work for publication. The other authors declare that they have no competing interests.

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Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1

Microscopic images of vaginal epithelial cells with attached biofilms. From left to right: Vaginal epithelial cells from patients with BV either with (BV biofilm +) or without biofilm (BV biofilm −) and after metronidazole treatment (cured). Top two rows: light microscopy of samples stained with crystal violet. Bottom two rows: scanning electron micrographs. Red arrows indicate EPS.

Fig. 2

Rank abundance and Shannon diversity of vaginal microbiota. a Dominance plot of cumulated samples from all visits. H health, vis/v visit, ex excluded, in included. b Shannon indices of all groups. Mean and quartile range are shown. Asterisks indicate significant (p < 0.01) differences assessed by a Wilcoxon rank sum test. c PCO of healthy women and included or excluded women with acute BV. d Cumulated abundances for each group. OTUs below 1% relative abundance are summarized as others.

Fig. 3

Biomarkers for biofilms in BV. LEfSe biomarker analysis comparing all samples from BV (visit 1) according to biofilm status (LDA threshold = 2.0).

Fig. 4

Composition of the vaginal microbiota of all women included in the study. Patients are separated according to treatment (LAP vs. WO 3191). Visits (1–5) and corresponding data (Nugent score, biofilm status, number of Amsel criteria and pH) are shown above and below. Red arrows indicate BV recurrence. OTUs below 1% abundance are summarized as “others”. LAP = lactic acid pessaries.

Fig. 5

The effect of metronidazole and pessaries. a Principal component analysis of the vaginal microbiota composition in healthy women and women after metronidazole treatment. Vectors indicate the species driving variation. H healthy cohort, V2 women from the clinical study at visit 2 (after metronidazole treatment). b The microbiota response to pessaries. Cumulated microbiota composition for LAP and WO 3191 treatment for all visits. At visit 1, metronidazole was provided. At visit 2, women were randomly assigned to one of the two pessary treatments. From visits 3 to 5, they had been treated with the respective pessary. OTUs below 1% abundance are summarized as “others”. LAP = lactic acid pessaries