Aims Identification of adherent-invasive Escherichia coli (AIEC) strains in IBD patients offers an opportunity to characterize the pathogenesis of microbial-induced intestinal inflammation.In which E.coli LF82 is the most typical AIEC strain.Although bacteria are implicated in the pathogenesis of chronic IBD, mechanisms of intestinal injury and immune activation remain unclear.Toll-like receptor 5 (TLR5) binding to bacterial flagellin activates NF-κB signaling and triggers an innate immune response to the invading pathogen.But the exact mechanisms of TLR5 involved in inflammation remains to be further studied.At present, the role and mechanism of AIEC and TLR5 in IBD still unknown.