Escherichia coli O157 Infection and Hemolytic Uremic Syndrome (HUS), 2004

During 2004, 110 culture-confirmed cases of Escherichia coli O157:H7 infection (2.2 per 100,000 population) were reported. This represents a 17% decrease from the 133 cases reported in 2003 and a 41% decrease from the median number of cases reported annually from 1997 to 2003 (median, 187 cases; range, 133 to 219). Forty-five (41%) cases occurred in residents of the Twin Cities metropolitan area. The remaining 65 cases occurred throughout Greater Minnesota. Eighty-four (76%) cases occurred during May through October. The median age of case-patients was 17.5 years (range, 4 months to 80 years). Thirty-nine (35%) case-patients were hospitalized; the median duration of hospitalization was 3 days (range, 1 to 82 days).

Five E. coli O157:H7 outbreaks were identified during 2004. Of these, two outbreaks were foodborne. The first foodborne outbreak was associated with consumption of frozen ground sirloin patties purchased from a membership grocery warehouse club; this outbreak resulted in four confirmed E. coli O157:H7 cases in Minnesota and one confirmed case in Wisconsin. The second foodborne outbreak was associated with consumption of custom slaughter ground beef used at a church spaghetti dinner served during a charity bicycle tour in Minnesota. Approximately 980 people participated in this event. Of 244 participants interviewed, 19 cases (14 from Minnesota) met the clinical case definition and seven had culture-confirmed E. coli O157:H7 infections. Of the 50 bicycle tour participants interviewed who reported eating the spaghetti dinner, 14 (28%) met the case definition. By extrapolation, an estimated 70 (28% of 250 persons served the spaghetti dinner) E. coli O157:H7 infections occurred as a result of this outbreak.

There were three daycare-associated outbreaks of E. coli O157:H7 in 2004, resulting in a total of 14 laboratory-confirmed cases (four to six cases per daycare). The route of transmission for all three outbreaks was likely person-to-person. There were no associated cases of hemolytic uremic syndrome (HUS).

In 2004, nine HUS cases were reported. There were no fatal cases. From 1997 to 2004, the median annual number of reported HUS cases was 14 (range, nine to 25), and the overall case fatality rate was 9%. In 2004, the median age of HUS case-patients was 7 years (range, 1 to 63 years). All cases occurred in either children (eight cases) or the elderly (one case). All nine case-patients were hospitalized, with a median hospital stay of 18 days (range, 1 to 82 days). All but one of the HUS cases reported in 2004 were post-diarrheal. E. coli O157:H7 was cultured from the stool of five case-patients. Non-O157 Shiga toxin-producing E. coli was isolated from two case-patients; the isolate from one was identified as E. coli O145:H28, the other serotype was not identified for the other case-isolate. E. coli O157:H7 serology was positive in one HUS patient with a negative stool culture. There were no outbreak-associated HUS cases in 2004.

• For up to date information see:E. coli O157:H7 and HUS
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2004