Enterotoxigenic Escherichia Coli (ETEC) is a type of Escherichia coli that can cause Escherichia coli enteritis and is commonly associated with the development of traveler’s diarrhea. A number of pathogenic isolates are termed ETEC, but the main hallmarks of this type of bacteria are expression of one or more enterotoxins and presence of fimbriae used for attachment to host intestinal cells.

Enterotoxins produced by ETEC include heat-labile (LT) enterotoxin and heat-stable (ST) enterotoxin. LT is similar to cholera toxin; it increases the level of cAMP in intestinal cells, and this causes an increase in electrolyte and water excretion (diarrhea). ST stimulates production of cGMP, also leading to increased fluid excretion and diarrhea. Because enterotoxic E. coli strains are non-invasive, they do not cause inflammation, bloody diarrhea, or systemic symptoms such as fever.