Effect and mechanism of the tnaA gene on probiotic EcN prevention of colitis in mice

This study investigated the role and mechanism of tnaA gene on Escherichia coli Nissle 1917, named EcN, in the prevention of colitis in mice. This study focused on the differences in indole secretion, biofilm, and inhibition of AIEC between the tnaA gene deletion and complementary strains of the pre constructed EcN bacteria and the wild strain of EcN, and explored the mechanism. Subsequently, we compared the preventive effects of WT and tnaA deleted strains of EcN on DSS induced colitis in mice and the differences in regulation of intestinal flora by pre gavage of bacteria. The final experimental results showed that the tnaA deleted strain secreted less indole, formed less biofilm, and was less motile, but had an enhanced inhibitory effect on pathogenic bacteria; gavage of both WT and tnaA deleted strains was effective in preventing colitis in mice, and pregavage of the tnaA deleted strain increased the abundance of the beneficial intestinal bacteria Lactobacillus reuteri, Akkermansia muciniphila, and Bacteroides acidifaciens.