Antimicrobial activity of lactobacilli metabolites on Staphylococcus aureus in vitro

Abstract

Antimicrobial activity of secondary metabolites that produced by Lactobacillus spp. has been investigated against clinical isolate of Staphylococcus aureus.Acidity effect of anaerobic fermentation of lactose in raw milk to lactic acid by Lactobacillus spp. was studied. The accumulation of acid in the medium lead to lowering pH of the yoghurt that prevent growth of Staph. aureus. The ability of clinical isolate was experimented for survival in acidic, alkaline, and neutralpH, the results showed that Staph. aureus have no growth in acidic pH while they have heavy growth in neutral and alkaline pH.This study confirmed the presence of synergistic effect between the secondary metabolites of lactobacilli and the acidity in yoghurt, which lead to inhibitory effect on the growth of Staph. aureus.