Escherichia coli O157 Infection
and Hemolytic Uremic Syndrome (HUS), 2003

During 2003, 133 culture-confirmed cases of Escherichia coli O157 infection (2.7 per 100,000 population) were reported. This represents a 17% decrease from the 160 cases reported in 2002 and a 35% decrease from the median number of cases reported annually from 1997 to 2002 (median, 204 cases; range, 160 to 219). Sixtyeight (51%) cases occurred in the Twin
Cities metropolitan area. The remaining 65 cases occurred throughout Greater Minnesota. One hundred eleven (83%) cases occurred from May through October. The median age of case-patients was 18 years (range, 9 months to 76 years). Forty-four (33%) case-patients were hospitalized; the median duration of hospitalization was 3 days (range, 1 to 36 days).

Four E. coli O157 outbreaks were identified during 2003. Among these, two outbreaks were foodborne: the first outbreak, resulting in five primary and two secondary confirmed E. coli
O157 infections in Minnesota residents, was associated with consumption of alfalfa sprouts traced to seeds imported from Australia by a Kentucky distributor. The second foodborne outbreak was associated with consumption of vacuum-packed frozen steaks sold door-to-door; this outbreak resulted in six confirmed and two probable E. coli O157 cases in Minnesota residents as well as single confirmed cases in Michigan, Kansas, Iowa, and North Dakota. One of the Minnesota case-patients developed HUS with serious neurologic sequelae.

The third E. coli O157 outbreak, resulting in three confirmed E. coli O157 cases, occurred in a daycare, and was likely transmitted person-toperson. The fourth outbreak was associated with attendance at a county fair and was likely transmitted by direct or indirect contact with animals. There were five confirmed cases among Minnesota residents and there was one confirmed case in a Nevada resident. One of the Minnesota cases developed HUS and was hospitalized for 36 days.

In 2003, nine cases of hemolytic uremic syndrome (HUS) were reported. There were no fatal cases. From 1997 to 2003, the mean annual number of reported HUS cases was 14 (range, nine to 22), and the overall case fatality rate was 9%. In 2003, the median age of HUS case-patients was 13 years (range, 1 to 58 years). Four case-patients were middle-aged (ages
48, 50, 52, and 58 years), an unusual age group for HUS, which occurs predominantly in children and the elderly. All nine case-patients were hospitalized, with a median hospital stay of 16 days (range, 5 to 36 days). All HUS cases occurred during June through September. As noted previously, there were two outbreak-related cases of HUS. All HUS cases reported in 2003 were post-diarrheal. E. coli O157:H7 was cultured from the stool of six case-patients and E. coli O145:H25 was cultured from the stool of one case-patient. E. coli O157 serology was positive in one HUS patient with a negative stool culture. One HUS patient had an undefined etiology.

• 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, 2003