Volunteer for NIAID-funded clinical studies related to E. coli on ClinicalTrials.gov.
While there are many types of E. coli bacteria, only certain types cause foodborne illness. Hundreds of harmless strains of E. coli can be found widely in nature, including the intestinal tracts of humans and other warm-blooded animals. Disease-causing strains, however, are a frequent cause of both intestinal and urinary-genital tract infections.
In 1982, scientists identified the first harmful foodborne strain of E. coli in the United States. The disease-causing foodborne E. coli most commonly found in this country is called O157:H7, which refers to chemical compounds found on the bacterium’s surface. Cattle are the main sources of E. coli O157:H7, but these bacteria also can be found in other domestic and wild mammals.
Several different strains of harmful E. coli can cause diarrheal disease.
Other types of E. coli, including O26:H11 and O111:H8, also have been found in the United States and can cause disease in people.
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Last Updated November 16, 2011