Etude de l’activité antagoniste de quelques souches de Lactobacillus sp. vis-à-vis de quelques pathogènes

Abstract

This work consists to show the existence of the antagonistic effect between lactic strains of the genus Lactobacillussp. isolated from goat's and camel milk against several pathogenic species by investigating inhibiting factors involved in these lactic acid bacteria. We studied the antagonistic action of 8 lactic strains (L1, L2, L4, LbM2a Lactobacillusplantarum, Lactobacillus rhamnosus Bbv2, Bifidobacterium lactis Bb12, Lactobacillus rhamnosus GG, Lactobacillus sake LTH 673 against the pathogenic strains :E. coli ATCC namely 10536, Pseudomonas aeruginosa ATCC27853, Bacillus cereus ATCC 9884, Shigella dysenteria CECT 457, Salmonella typhimurium ATCC 13311, Listeria monocytogenes ATCC 13932 and Carnobacterium maltoaromaticum DSM 20722, using the diffusion method ADT in wells. Their interactions has led to the emergence of significant inhibition zones, in effect, the GG strain recorded the largest inhibition zone with a diameter of about 15 mm againstShigella dysenteriae. Neutralization of supernatants of the Lactobacillus strains tested showed the persistence of antagonistic action againstB. cereus, Carnobacterium maltoaromaticum and Listeria monocytogenes with a maximum of 13 mm exerted by the Bb12 strain againstSalmonella typhimurium. The results showed that these inhibiting agents are likely bacteriocins, which represents the possibility of exploiting them in the future in food industry.