A nationwide case-control study of Escherichia coli O157:H7 infection in the United States
A nationwide case-control study of Escherichia coli O157:H7 infection in the United States. Slutsker L, Ries AA, Maloney K, Wells JG, Greene KD, Griffin PM. The Journal of Infectious Diseases 1998;177(4):962-966.
Surveillance data indicate that most infections due to Escherichia coli O157:H7 do not occur in the setting of recognized outbreaks. In addition, by definition, outbreak investigations represent situations that are geographically and temporally circumscribed. This study sought to investigate risk factors for sporadic E. coli O157:H7 infection by conducting a two-year case-control study in 10 medical centers throughout the United States. Among 73 case-patients and 142 matched controls, exposures in the seven days before illness associated with E. coli O157:H7 infection in univariate analysis included consumption of hamburger, undercooked hamburger, or hot dogs, eating at a fast-food restaurant, drinking unchlorinated well water, swimming in a pond, and having a household member with diarrhea. In multivariate analysis, only eating undercooked hamburger remained associated with infection. Seven (8%) of 93 patients developed hemolytic uremic syndrome (HUS). Patients with HUS had a lower median age (7 years) than those without HUS (30 years). The only other risk factor identified was vomiting within three days of diarrhea onset. Although treatment with an antimicrobial agent within three days of diarrhea onset was not associated with HUS overall, patients less than 13 years of age who developed HUS were more likely to have received an antimicrobial agent within three days after diarrhea onset than were those who either received an antimicrobial agent more than three days after diarrhea onset, or who did not receive any antimicrobial agents. One patient with HUS, a 22-month-old girl, died after a 3-month hospitalization complicated by chronic renal failure and stroke. These data suggest that children who present with vomiting within three days of diarrhea onset should have their hematologic and renal function closely monitored. Caution is advised in the use of antimicrobial agents in younger patients.