Effects of probiotic Saccharomyces cerevisiae on Candida parapsilosis biofilm and antifungal efficacy in vitro and in a murine model in Türkiye

Introduction

This study investigated the effects of the probiotic Saccharomyces cerevisiae on Candida parapsilosis biofilm formation and antifungal susceptibility in vitro and evaluated its potential to enhance antifungal efficacy in a murine candidiasis model. Methodology: C. parapsilosis ATCC 22019 and S. cerevisiae ATAFM-2021 were tested with fluconazole (FLU), caspofungin (CAS), and amphotericin B (AMB). Biofilm formation was quantified using the crystal violet assay under mono- and co-culture conditions with different inoculation timings. Antifungal susceptibility was assessed by microbroth dilution and checkerboard methods, and interactions were interpreted using the fractional inhibitory concentration index (FICi). In vivo candidiasis was induced in BALB/C mice. Antifungals were administered intraperitoneally for five days starting 24 hours after infection, while the probiotic was supplied in drinking water either 14 days before infection or</