Biosurfactant from vaginal Lactobacillus crispatus BC1 as a promising agent to interfere with Candida adhesion

Background Lactobacillusspp. dominating the vaginal microbiota of healthy women contribute to the prevention of urogenital and sexually transmitted infections. Their protective role in the vagina can be mediated byLactobacilluscells themselves, metabolites or bacterial components, able to interfere with pathogen adhesion and infectivity. Vulvovaginal candidiasis (VVC) is a common genital infection, caused by the overgrowth of opportunisticCandidaspp. includingC. albicans, C. glabrata, C. kruseiandC. tropicalis. Azole antifungal drugs are not always efficient in resolving VVC and preventing recurrent infections, thus alternative anti-Candidaagents based on vaginal probiotics have gained more importance. The present work aims to chemically characterize the biosurfactant (BS) isolated from a vaginalLactobacillus crispatusstrain,L. crispatusBC1, and to investigate its safety and antiadhesive/antimicrobial activity againstCandidaspp., employing in vitro and in vivo assays. Results BS isolated from vaginalL. crispatusBC1 was characterised as non-homogeneous lipopeptide molecules with a critical micellar concentration value of 2 mg/mL, and good emulsification and mucoadhesive properties. At 1.25 mg/mL, the BS was not cytotoxic and reducedCandidastrains' ability to adhere to human cervical epithelial cells, mainly by exclusion mechanism. Moreover, intravaginal (i.va.) inoculation of BS in a murine experimental model was safe and did not perturb vaginal cytology, histology and cultivable vaginal microbiota. In the case of i.va. challenge of mice withC. albicans, BS was able to reduce leukocyte influx. Conclusions These results indicate that BS from vaginalL. crispatusBC1 is able to interfere withCandidaadhesion in vitro and in vivo, and suggest its potential as a preventive agent to reduce mucosal damage occasioned byCandidaduring VVC.