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.