(1) Pathogenic Escherichia coli mainly includes four types. In addition to heat-resistant or heat-labile enterotoxin produced by enterotoxigenic Escherichia coli, cholera-like watery diarrhea is caused. Other pathogenic Escherichia coli can invade intestinal mucosal epithelial cells, produce Shiga-like toxins and cause bloody diarrhea similar to dysentery.
(2) Typhoid Bacillus, its pathogenic feature is that bacteria invade and colonize the intestinal submucosa lymphoid tissue from the digestive tract, grow in macrophages, and can spread to the whole body through bacteremia, releasing strong endotoxin and causing systemic poisoning symptoms. The same is true of bacteria spreading from bacteremia to bile bonds.
Bile re-entering the lymphatic tissue of intestinal wall can cause ulcer, bleeding and even perforation.
(3) Shigella dysenteriae mainly relies on pili adhesion and can invade intestinal mucosal epithelial cells, producing endotoxin and Shiga toxin (exotoxin, produced by Shigella dysenteriae), causing purulent stool and systemic poisoning symptoms.
(4) Vibrio cholerae, which grows on the surface of intestinal mucosal epithelial cells after oral infection, produces cholera enterotoxin, promotes cell secretion function and causes severe watery diarrhea.