BackgroundThe urinary microbiota is similarly complex as the vaginal and penile microbiota, yet its role as a reservoir for pathogens and for recurrent polymicrobial biofilm diseases like bacterial vaginosis (BV) is not clear.ResultsHere, we analysed the urinary microbiota of healthy men and women and compared it with that of women during BV and after antibiotic treatment using next-generation sequencing of the 16S rRNA gene V1-V2 regions. Eight different community types, so called urotypes (UT), were identified in healthy humans, all of which were shared between men and women, except UT 7, dominated in relative abundance by Lactobacillus crispatus, which was found in healthy women only. Orally applied metronidazole significantly reduced Shannon diversity and the mean relative abundance of Gardnerella vaginalis, Atopobium vaginae, and Sneathia amnii, while L. iners increased to levels twofold higher than those found in healthy women. Although individual urine microbial profiles strongly responded to the antibiotic, the healthy community could not be restored. The correlation between urinary and vaginal fluid microbiota was generally weak and depending on UT and BV status. It was highest in UT 1 in acute BV (59% of samples), but after metronidazole treatment, only 3 out of 35 women showed a significant correlation between their urinary and vaginal microbiota composition.ConclusionsUrethra and bladder thus harbor microbial communities distinct from the vagina. The high abundance of BV related species in the urine of both men and women suggests that urine may act as a reservoir of pathogens and contribute to recurrence.Trial registrationClinicalTrials.gov, NCT02687789 Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-017-0305-3) contains supplementary material, which is available to authorized users.

Bacterial vaginosis is a serious issue for women in their reproductive years. Although it can usually be cured by antibiotics, the recurrence rate is very high, and some women do not respond to antibiotic therapy. The reasons for that are not known. Therefore, we undertook a study to detect the activity of the complete microbiota in the vaginal fluid of women who responded to antibiotic therapy and compared it to the activity of the microbiota in women who did not respond. We found that one of the most important pathogens in bacterial vaginosis, Gardnerella vaginalis, has activated genes that can repair the DNA damage caused by the antibiotic in those women that do not respond to therapy. Suppressing these genes might be a possibility to improve the antibiotic therapy of bacterial vaginosis.

BackgroundBacterial 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.ResultsHere, 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.ConclusionsStabilizing 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 registrationClinicalTrials.gov NCT02687789 Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-017-0326-y) contains supplementary material, which is available to authorized users.

Bacterial vaginosis (BV) is a common infection in reproductive age woman and is characterized by dysbiosis of the healthy vaginal flora which is dominated by Lactobacilli, followed by growth of bacteria like Gardnerella vaginalis. The ability of G. vaginalis to form biofilms contributes to the high rates of recurrence that are typical for BV and which unfortunately make repeated antibiotic therapy inevitable. Here we developed a biofilm model for G. vaginalis and screened a large spectrum of compounds for their ability to prevent biofilm formation and to resolve an existing G. vaginalis biofilm. The antibiotics metronidazole and tobramycin were highly effective in preventing biofilm formation, but had no effect on an established biofilm. The application of the amphoteric tenside sodium cocoamphoacetate (SCAA) led to disintegration of existing biofilms, reducing biomass by 51% and viability by 61% and it was able to increase the effect of metronidazole by 40% (biomass) and 61% (viability). Our data show that attacking the biofilm and the bacterial cells by the combination of an amphoteric tenside with the antibiotic metronidazole might be a useful strategy against BV.

Bacterial vaginosis (BV) is a prevalent multifactorial disease of women in their reproductive years characterized by a shift from the Lactobacillus spp. dominated microbial community towards a taxonomically diverse anaerobic community. For unknown reasons, some women do not respond to therapy. In our recent clinical study, out of 37 women diagnosed with BV, 31 were successfully treated with metronidazole, while 6 still had BV after treatment. To discover possible reasons for the lack of response in those patients, we performed a metatranscriptome analysis of their vaginal microbiota, comparing them to patients who responded. Seven out of 8 Cas genes of Gardnerella vaginalis were highly up-regulated in non-responding patients. Cas genes, in addition to protecting against phages, might be involved in DNA repair thus mitigating the bactericidal effect of DNA damaging agents like metronidazole. In the second part of our study, we analyzed the vaginal metatranscriptomes of four patients over three months and showed high in vivo expression of genes for pore-forming toxins in L. iners and of genes encoding enzymes for the production of hydrogen peroxide and D-lactate in L. crispatus.