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

There is an increasing interest in yeasts isolated from natural sources to be used as probiotics. Saccharomyces-based probiotics have been proposed as a valid alternative to the conventional 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 in comparable properties to all those exhibited by the commercial probiotic Saccharomyces boulardii. Then, we checked the antagonistic activity of the new isolate against some clinical fluconazole resistant C. albicans strains, showing its ability to inhibit filamentation, biofilm formation, and the 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 against C. albicans.