Zeinab Sadeghi Ardestani - Department of Medical Mycology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Mohammad hossein Yadegari - Department of Medical Mycology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Reza Kachuei - Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.

Backgrounds: The fungal pathogen Candida albicans is a cause of biofilm formation in patients with oropharyngeal candidiasis. Saccharomyces boulardii is a nonpathogenic fungal probiotic that plays an important role in preventing or treating intestinal diseases. This research aimed to determine the inhibitory effect of S. boulardii probiotic yeast on biofilm formation capacity of C. albicans, which is one of the main virulence factors. Materials & Methods: In this study, ۳۳ oropharyngeal samples were collected from patients with suspected oropharyngeal candidiasis (OPC). The inhibitory activity of S. boulardii against biofilm formation capacity of C. albicans was investigated by crystal violet-based staining (CVS) and MTT reduction reaction. The collected data were analyzed using student's t-test in SPSS statistical software. Findings: In this study, the probiotic yeast S. boulardii reduced the pathogenicity and virulence of C. albicans in vitro. According to the results of CVS and MTT assays, a considerable reduction (p< .۰۰۱) in the biomass and viability of C. albicans biofilms was observed after ۴۸ hours of incubation in the presence of S. boulardii extract. Conclusion: There was a significant association between S. boulardii extract concentration and biofilm formation in both CVS and MTT assays. Biofilm formation decreased with increasing S. boulardii extract concentration and incubation time in both methods compared to the control group.

Candida albicans, Saccharomyces boulardii, Biofilm, Crystal violet, MTT