High-efficiency anti-enterotoxigenic activity of Lactobacillus on staphylococcal enterotoxins biosynthesis

Abstract

Staphylococcal enterotoxins (SEs) are the main reason for the pathogenicity of Staphylococcus aureus, and finding a suitable inhibitory agent against their production is necessary for the food industry. The aim of this study was the finding a mixture of Lactobacillus strains with the highest anti-enterotoxigenic activity (AEA) against the production of A and B enterotoxins from S. aureus grown on medium including sub-minimum inhibitory concentrations of cell-free supernatant (CFS) of three Lactobacillus species using by real-time PCR and statistical method of mixture design. Results showed the antibacterial activity (AA) of CFS of Lactobacillus strains on S. aureus was higher than their microbial suspensions. Among the Lactobacillus isolates evaluated in this study, CFS of L. brevis isolated from fermented olive had higher AA against S. aureus and its A and B enterotoxins production. A synergistic inhibitory effect was observed between CFSs of L. brevis isolated from fermented olive, L. plantarum isolated from fermented olive and L. brevis isolated from pickled garlic. The highest AEA was observed by treatment with a mixture containing 45% CFS of L. brevis isolated from fermented olive, 27% CFS of L. plantarum isolated from fermented olive, and 28% CFS of L. brevis isolated from pickled garlic.