Exploration de l'effet antimicrobien des souches lactiques

Abstract

The antibacterial activity of six strains of lactic acid bacteria (LB1; LB2; LB3; LB4; LB5 and BB12) is tested against pathogenic strains. To determine the inhibitory effect of lactic acid strains, direct methods such as the agar spot test, and the indirect method by the agar well diffusion test were used for the cell fraction (bacterial culture) and the extracellular fraction(native supernatant, neutralized and treated with pepsin), respectively, in order to determine the nature of the inhibitory substance. The results showed that most strains have an inhibitory effect against all pathogens and the best inhibitory zones were obtained by the strains (LB2, Lb4 et BB12) with a diameter of (12mm) . This effect is due to different metabolites such as lactic acid, H2O2, Diacétyle or proteins substances which would be responsible for this inhibitory effect.