Evaluation of the inhibitory activity of Shiga-like toxin producing Escherichia coli by Lactobacillus spp. isolated from pigs

RUIZ, M.J.; COLELLO, R.; PADOLA, N.L.; ETCHEVERRÍA, A.I.

Mar del Plata

Congreso; X Congreso de Microbiología General Samige; 2014

SAMIGE

Foodborne diseases represent health and economic problems of relevance in the world. Symptoms vary depending on the causal agent, the dose of intake and the age of the group affected. Bacteria most implicated are Shiga-like toxin producing Escherichia coli (STEC). To reduce the risk of infection by pathogen is necessary a strict microbiological monitoring throughout the food production chain. One strategy is the use of biopreservation systems as lactic acid bacteria or their metabolites. The genus Lactobacillus is of interest as new biotechnological applications and by their probiotic properties. Usually, these strains are isolated from humans because of their greater ability to adhere to and colonize the intestinal epithelium. However studies have shown that strains of Lactobacillus isolated from animals also have beneficial effects on human. Through this study, it was determinate the inhibitory activity of Lactobacillus spp. isolated from pigs. This was evaluated on EDL933 STEC reference strain isolated from a case of hemolytic uremic syndrome. Lactobacillus spp. was inoculated by puncture on MRS agar plates. After incubation, the plates were exposed to chloroform vapors for inactivating bacteria. Later, the plates were covered with LB agar containing STEC. Finally, the inhibitory activity was evaluated by observing the translucent area around the colony. Of the three strains tested, two inhibited growth of STEC, with the halo of inhibition greater than 1 mm. This suggests that Lactobacillus have characteristics of antagonism against pathogens. It could be concluded that the biopreservation ability of Lactobacillus spp. generates alternatives for producing foods naturally protected and improve the microbiological quality in the food industry.