MUC5AC and inflammatory bowel disease: The enrichment of Escherichia-Shigella is a potential characteristic of IBD patients and an initiator of IBD pathogenesis, including the stimulation of mucin degradation by proteases, adhesion and invasion of intestinal epithelial cells, and promotion of the secretion of pro-inflammatory cytokines and chemokines (Liu et al., 2022) (Mazzarella et al., 2017).