Inhibitory effect of Saccharomyces cerevisiae supernatant and lysate on expression of lasB and apl genes of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen. Elastase and alkaline protease are two major virulence factors in this bacterium. Today, probiotics is one of the most comprehensive way to treat and prevent diseases. The aim of this study was the evaluation the effect of Saccharomyces cerevisiae S3 on the expression of elastase (lasB) and alkaline protease (apl) genes. In the first stage, S. cerevisiae S3 supernatant and lysate were prepared. Then, subminimum inhibitory concentrations (sub-MIC) of both supernatant and lysate were applied to P. aeruginosa PAO1. The expression of lasB and apl were measured by real-time PCR method. The supernatant of the probiotic decreased the apl gene expression and increased expression of lasB. The lysate extract decreased the expression of lasB and apl. The results of this study showed that S. cerevisiae S3 had an inhibitory effect on some virulence factors of P. aeruginosa. Further experiments on the influence of S. cerevisiae on other virulence factors of P. aeruginosa and pathogens are suggested.