RT Journal T1 EScherichia coli o157 and children JF Archives of Pediatrics & Adolescent Medicine JO Archives of Pediatrics & Adolescent Medicine YR 2009 FD January 5 VO 163 IS 1 SP 96 OP 96 DO 10.1001/archpediatrics.2008.535 UL http://dx.doi.org/10.1001/archpediatrics.2008.535 AB The strain of E coli that causes the most serious illness in humans is a strain called E coli O157:H7, sometimes called E coli O157. The people most at risk for infection with this strain of E coli are the very young and very old, but anyone can become ill if infected. Rates of E coli O157 have gone down in recent decades; there are around 70 000 infections with E coli O157 each year in the United States. The most important risk factor for this illness is bloody diarrhea.