Vaginal Lactobacillus gasseri biosurfactant: a novel bio- and eco-compatible anti-Candida agent

Vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC), caused by <i>Candida</i> spp. overgrowth, are common and challenging infections of the genital tract. Among <i>Candida</i> virulence factors, the ability to adhere to host epithelium and to form biofilms are frequently retrieved, especially in RVVC. Vaginal pathogen overgrowth is counteracted by resident lactobacilli, which exert a barrier thanks to the production of antimicrobial metabolites, such as biosurfactants (BS). BS was recovered from vaginal <i>Lactobacillus gasseri</i> BC12 and its chemical characteristics as well as its ability to lower the surface tension and to emulsify two different immiscible phases were investigated. BS showed the typical features of a lipopeptide with a critical micellar concentration of 1.2 mg/mL. BS showed antibiofilm activity towards various <i>Candida albicans</i> and non-<i>albicans</i> isolates, notably, it was able to prevent biofilm formation and eradicate preformed biofilms. The absence of cytotoxicity of BS and its ability to counteract the adhesion of <i>Candida</i> spp. were highlighted on HeLa cells through MTT and competition/exclusion assays, respectively. The environmental impact of BS was also investigated on a microcosm model (spring water) by culture-based and molecular (16S rRNA-targeted Illumina sequencing) methods, and no remarkable modifications in the taxonomy composition of the bacterial ecosystem were observed. To conclude, BS from <i>L. gasseri</i> BC12 appears as a promising, biocompatible and environmentally friendly approach to prevent and treat VVC/RVVC.