Which strain of E.coli is known for causing severe gastrointestinal illness?

E. coli O157:H7 is a specific strain of Escherichia coli that is recognized for causing severe gastrointestinal illness. This strain produces a toxin known as Shiga toxin, which can lead to serious health complications, including bloody diarrhea and hemolytic uremic syndrome (HUS), particularly in vulnerable populations such as young children and the elderly. E. coli O157:H7 is often associated with contaminated food and water, particularly undercooked ground beef, unpasteurized dairy products, and raw vegetables.

In contrast, while other pathogens listed can cause foodborne illnesses, they are not primarily associated with the severe gastrointestinal symptoms that E. coli O157:H7 is known for. Bacillus cereus is associated with food poisoning symptoms such as nausea and vomiting, but those symptoms typically arise from a different mechanism. Yersinia can also cause gastrointestinal infections but is not as frequently linked to severe illness as E. coli O157:H7. Vibrio species can cause foodborne illness, usually associated with seafood, but do not have the same level of association with severe gastrointestinal problems as the E. coli strain in question.