大肠杆菌是人类和大多数温血动物肠道中的正常菌群。一般而言,寄生于人类肠道的大肠杆菌是无害的共生菌,并且对于维持肠道的菌群平衡,人体所需要的一些重要物质的吸收或合成有重要作用。但有某些菌株可引起不吲症状的腹泻,与食物源性疾病有关,因之称为致病性大肠杆菌。因为本类细菌所引起的临床症状以腹泻为主,故也称之为致泻性大肠杆菌。根据不同的毒力性质,与肠粘膜 E. coli is a normal flora in the gut of humans and most warm-blooded animals. In general, Escherichia coli parasites in the human intestine are innocuous commensal bacteria and play an important role in the absorption or synthesis of some important substances required by the body for maintaining the balance of the intestinal flora. However, some strains can cause symptoms of non-indole diarrhea, and food-borne diseases, so called pathogenic Escherichia coli. Because of this class of bacteria caused by clinical symptoms of diarrhea, it is also called diarrhea Escherichia coli. Depending on the nature of the virulence, and intestinal mucosa