Protective Effect of Probiotics Strains in Ruminants

Shiga toxin-producing Escherichia coli (STEC) strains are food-borne pathogens that cause human diseases, and ruminants are usually important reservoirs of STEC. The first step of enteric infection is colonization of the host’s gut mucosal surface by pathogenic strains of bacteria. Probiotic bacteria can decrease the severity of infection by competing for receptors and nutrients and by synthesizing an acid that creates an unfavorable environment for the growth of several bacterial species. The aim of this study was to determine whether the inoculation of sheep with a mixture containing 5 x 108 (CFU) of Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus bulgaricus, Lactobacillus lactis, Streptococcus thermophilus and Enterococcus faecium per animal decreases the shedding at animals previously inoculated with STEC nonO157. Sheep that received oral inoculums containing 2 × 109 viable bacteria of STEC carriers of stx1, stx2 and eae genes were compared with others groups that did not receive inoculums. When probiotic was inoculated together with the STEC non-O157, the numbers of these same bacteria in a fecal sample were lower than the group did not receive. It occurred during the 3th, 5th, 6th and 7th weeks postinoculation. Thus, we conclude that this mixture likely presented a potential protective effect in reducing colonization by STEC non-O157 and can be used as an alternative method to decreases STEC non-157 infection in sheep, thereby reducing transmission to humans.