inhibitory effect of probiotic yeast saccharomyces cerevisiae on biofilm formation and expression of α-hemolysin and enterotoxin a genes of staphylococcus aureus

Background and objectives: staphylococcus aureus, as an opportunistic pathogen, is the cause of a variety of diseases from mild skin infections to severe invasive infections and food poisoning. increasing antibiotic resistance in s. aureus isolates has become a major threat to public health. the use of compounds produced by probiotics can be a solution to this problem. thus, the purpose of this study was to investigate the effect of saccharomyces cerevisiae on some virulence factors (biofilm, α-hemolysin, and enterotoxin a) of s. aureus. materials and methods: supernatant and lysate extracts were prepared from s. cerevisiae s3 culture. sub-mic concen- trations of both extracts were separately applied to s. aureus atcc 29213 (methicillin-sensitive s. aureus; mssa) and s. aureus atcc 33591 (methicillin-resistant s. aureus; mrsa) strains. biofilm formation of these strains was measured by microtiter plate assay and expression level of α-hemolysin and enterotoxin a genes (hla and sea, respectively) using real-time pcr technique. results: the supernatant extract has reduced both biofilm formation and expression of sea and hla genes, while lysate ex- tract had only anti-biofilm effects. the mrsa strain showed more susceptibility to yeast extracts than mssa strain in all tests. conclusion: the present study exhibited favorable antagonistic effects of s. cerevisiae s3, as a probiotic yeast, on mssa and mrsa strains. based on the findings of this study, the compounds produced by this yeast can be used to control s. aureus infections; however, further similar studies should be conducted to confirm the findings of the present study.