[Bacterial enterotoxins: structure, mode of action].

The enterotoxins are macro-proteins, produced by enterotoxic bacterial strains acting in the human or animal intestine during digestive infections. In most cases, they induce diarrhoea (associated or not with tissue damage). These molecules differ in their structure and mechanism of action. Some of them (cholera toxin, Escherichia coli LT) activate a cyclase system (adenylate or guanylate cyclase), inducing water and electrolyte flux in the gut. Conversely, others (toxins A and B, Clostridium difficile; Clostridium perfringens enterotoxin; verotoxin), provoke diarrhoea, intestinal damage associated with inflammatory response acting on cellular functions (protein synthesis, permeability to small molecules). Most enterotoxins act via membrane receptors which they specifically recognize on the surface of the enterocyte.