Biotherapeutic Potential of a Novel Probiotic Kluyveromyces marxianus Isolated from a Sourdough Starter Against Vaginal C. albicans Strains

There is an increasing interest in yeasts isolated from natural sources to be used as probi-otics. Saccharomyces-based probiotics have been proposed as a valid alternative to the con-ventional drug therapy for the prevention and treatment of vulvovaginal candidiasis, also considering the resistance of some Candida strains to many antifungals. Here we isolated from an artisanal sourdough a new yeast strain which was identified as Kluyveromyces marxianus and assessed its probiotic and safety properties, which resulted comparable at all to those exhibited by the commercial probiotic Saccharomyces boulardii. Then, we checked the antagonistic activity of the new isolate against some clinical fluconazole re-sistant C. albicans strains, showing its ability to inhibit filamentation, biofilm formation, and adhesion of C. albicans to vaginal epithelial A-431 cells. Also, K. marxianus reduced the cell damage provoked by C. albicans and the expression of SAP2 and SAP6 genes. On the whole, our results enlarge the spectrum of the beneficial properties of the food-grade yeast K. marxianus showing for the first time its biotherapeutic potential as anticandidal agent.