Among the potential mechanisms of action identified for the microbicidal activity of EcN are the enhancement of transepithelial resistance [35], a beneficial effect on the formation and stabilization of epithelial tight junctions [36], the positive regulation of zona occludens-1 mRNA expression [37], the induction of human β-defensin 2, an inducible antimicrobial peptide synthesized by the epithelium to counteract bacterial adhesion and invasion [38], and a protective role against pathogenic E. coli strains that colonize the intestines of patients with inflammatory bowel disease [19]. This evidence concerns the gene TJP1 and inflammatory bowel disease.