Abstract

The aim of this study was to examine the reduction of enterotoxigenic Escherichia coli (ETEC) colonization by oral administration of Lactobacillus casei as probiotic in a murine model. In this study, thirty-six BALB/c mice were divided to two test groups and one control group. One of the test groups was fed probiotic bacteria at six days and other groups at three days; whereas, the control group did not receive any probiotic. 72 h after the last oral administration of probiotic, the all three groups were fed by the ETEC. Than, the numbers of E. coli excreted from animal intestinal were determined at various times by colony counting on specific culture media and assessed their rate of colonization. The results of this study showed that L. casei is enable to be colonize in the murine gastrointestinal tract and both test groups of murine show significant decrease of ETEC excretion compared to control group (P = 0.001). Also, comparison of test groups indicated that longer time reception of probiotic bacteria resulted in more reduction of colonization of pathogenic bacteria. These findings suggest that L. caseican be used as a candidate probiotic to reduce the rate of colonization and establishment of ETEC in the digestive tract and to prevent diarrhea caused by this organism.

Key words: Lactobacillus casei sp. strain GG, Escherichia coli, probiotic, enterotoxigenic traveler's diarrhea, bacteriotherapy