enterotoxins

Enterotoxins are toxins that target the cells of the gastrointestinal tract, especially the intestinal mucosa, to produce secretory diarrhea and often vomiting. They can be produced by various bacteria, sometimes preformed in contaminated food and, in other cases, produced in the gut after ingestion. Enterotoxins are distinguished from toxins with primarily systemic or cytotoxic effects.

Many enterotoxins act by altering ion transport in enterocytes. Cholera toxin and the heat-labile toxin of enterotoxigenic Escherichia coli increase intracellular cAMP, stimulating chloride secretion and water loss. The heat-stable toxins of E. coli increase intracellular cGMP by activating guanylate cyclase, also promoting fluid secretion. Other enterotoxins disrupt intestinal tight junctions or the mucosal barrier, contributing to diarrhea; staphylococcal enterotoxins are potent emetogens that function as superantigens, triggering cytokine release in the gut.

Notable enterotoxins include cholera toxin from Vibrio cholerae; heat-labile and heat-stable enterotoxins from E. coli; staphylococcal enterotoxins SEA through SEE; and enterotoxins produced by Bacillus cereus and Clostridium perfringens. These toxins vary in heat stability, with some remaining active after cooking.

Clinical presentation ranges from rapid-onset vomiting and profuse watery diarrhea to milder gastroenteritis. Preformed toxins in food can cause symptoms within hours; toxins produced in vivo may have a longer onset. Diagnosis relies on detection of toxin or toxin genes in clinical samples or food, supported by epidemiological linkage.

Management focuses on fluid and electrolyte replacement and supportive care. Antibiotics are not routinely required for most enterotoxin-mediated illnesses. Prevention emphasizes proper food handling and cooking, adequate refrigeration, and, for cholera, vaccination in appropriate settings.