Hemolytic Uremic Syndrome After an Escherichia coli O111 Outbreak.

Background: In August 2008, the largest known US serotype 1 Escherichia coli O111 outbreak occurred in Oklahoma, causing 341 illnesses, including hemolytic uremic syndrome (HUS). HUS is not well described in non-O157 E coli outbreaks but occurs in 2% to 15% of O157 infections, predominantly among children. We examined outbreak-related hospitalizations to characterize E coli O111 illness, the HUS attack rate, and factors associated with subsequent HUS diagnosis among hospitalized patients.