The emerging clinical importance of non-O157 Shiga toxin-producing Escherichia coli.

In 1982, hemorrhagic colitis and hemolytic-uremic syndrome were linked to infection with Escherichia coli O157:H7, a serotype now classified as Shiga toxin-producing E. coli (STEC). Thereafter, hemorrhagic colitis and hemolytic-uremic syndrome associated with non-O157 STEC serogroups were reported, with the frequency of non-O157 STEC illness rivaling that of O157:H7 in certain geographic regions. In the United States, non-O157 E. coli may account for up to 20%-50% of all STEC infections. A high index of suspicion, paired with options to test for non-O157 STEC infection, are necessary for early recognition and appropriate treatment of these infections. Supportive care without the use of antibiotics is currently considered to be optimal treatment for all STEC infections. This commentary provides a perspective on the non-O157 STEC as human pathogens, how and when the clinician should approach the diagnosis of these organisms, and the challenges ahead.