Screening of lactobacilli with antagonistic activity against enteroinvasive Escherichia coli

In the present study, 339 lactic acid bacteria (LAB) strains, isolated from fermented dough, pickles, salted meat, baby feces and fermented dairy products, were screened for the antagonistic activity against enteroinvasive Escherichia coli (EIEC). Through the analysis of the inhibition zone of the lactobacilli spent culture supernatant on the growth of EIEC, 22 LAB strains were selected for further analysis. Using the in vitro assays of adhesion to HT-29 cell lines and tolerance to gastrointestinal conditions (acid and bile), two isolates, Lactobacillus plantarum CCFM 233 and L. plantarum CCFM 231 were shown not only to inhibit the growth of EIEC significantly, but also to have high adhesion to HT-29 cell lines and good tolerance to low acid and high bile. Furthermore, the two strains could strongly antagonize the adhesion and invasion of EIEC to the HT-29 cell lines. This study suggests that L. plantarum CCFM 233 and L. plantarum CCFM 231 could be used as potential probiotics in food applications against EIEC.