The right bug in the right place: opportunities for bacterial vaginosis treatment

Abstract

Bacterial vaginosis (BV) is a condition in which the vaginal microbiome presents an overgrowth of obligate and facultative anaerobes, which disturbs the vaginal microbiome balance. BV is a common and recurring vaginal infection among women of reproductive age and is associated with adverse health outcomes and a decreased quality of life. The current recommended first-line treatment for BV is antibiotics, despite the high recurrence rate. Live biopharmaceutical products/probiotics and vaginal microbiome transplantation (VMT) have also been tested in clinical trials for BV. In this review, we discuss the advantages and challenges of current BV treatments and interventions. Furthermore, we provide our understanding of why current clinical trials with probiotics have had mixed results, which is mainly due to not administering the correct bacteria to the correct body site. Here, we propose a great opportunity for large clinical trials with probiotic strains isolated from the vaginal tract (e.g., Lactobacillus crispatus) and administered directly into the vagina after pretreatment.

Fig. 1. Overview of the strategy on vaginosis treatment with probiotics.

a Lactobacillus-dominated vaginal microbiome environment. Vaginal Lactobacillus species, such as Lactobacillus crispatus, produce lactic acid, bacteriocins, and hydrogen peroxide (H₂O₂), which may provide protection against bacterial vaginosis (BV) related bacteria and other infections. b BV microbiome environment. BV-related bacteria (mainly Gardnerella) induce inflammation in the vaginal tract and form a biofilm on vaginal epithelial cells. The latter probably increases antibiotic resistance and refractoriness to probiotic treatment. Short chain fatty acids (SCFAs) produced by BV-related bacteria, increase vaginal pH. In addition, catabolism of amino acids and mucosal proteins results in amines and a thinner mucosal layer in the vaginal tract. c Treatment of BV with probiotics. Pretreatment such as antibiotic, bacteriophage, anti-biofilm, or antimicrobial agents, in combination with vaginal probiotic species and vaginal administration, increase the probability of successful colonization. Note: figure was created with BioRender.com.