The effect of probiotic yeast Saccharomyces cerevisiae on Staphylococcus aureus biofilm formation

Biofilm formation is an important virulence factor in Staphylococcus aureus. Most infections associated with biofilm of this bacterium are difficult to treat with antibiotics. As yet, a lot of mechanisms have been explained for probiotic yeast functions against bacterial infections, but few studies have been done on their effects on biofilm formation. The aim of this study was to evaluate the effect of Saccharomyces cerevisiae yeast on Staphylococcus aureus biofilm formation.
Extract of supernatant and lysate was prepared from Saccharomyces cerevisiae culture. After determining the MIC, the effect of extracts at three concentrations of 2048, 1024 and 512 µg/ml was evaluated on biofilm formation of two standard strains of S. aureus, ATCC 29213 (methicillin-sensitive) and ATCC 33591 (methicillin-resistant) using the microtiter plate assay in three replications.
Both supernatant and lysate extract of yeast could significantly reduce the biofilm formation of both methicillin-sensitive and resistant strains of S. aureus at all concentrations. While both studied strains were strong biofilm producers, at the concentration of 2048 µg/ml, supernatant could reduce their biofilm formation to moderate level. Also, lysate reduced biofilm formation to weak level more effectively.
In this study, the good effect of S. cerevisiae yeast on the reduction of S. aureus biofilm formation was observed for the first time. Doing more studies, it is expected to treat infections caused by biofilm of this bacterium with probiotic yeasts.