Interaction of AIEC with intestinal mucosa in the context of IBD include: (1) AIEC cross the mucous layer and resist antimicrobial peptides; (2) AIEC adhere to intestinal epithelial cells (IECs) via FimH and carcinoembryonic antigen related cell adhesion molecule 6 (CEACAM6), and lead to colonisation of the gut mucosa; (3) AIEC enter lamina propria and Peyer’s patches across M cells via long polar fimbriae (LPF) expression, and interact with immune cells (Palmela et al., 2018). The gene discussed is CEACAM6; the disease is inflammatory bowel disease.