Purpose: To describe an outbreak ofEscherichia coli O175:H7 infection resulting in a high rate of progression to hemolytic-uremic syndrome, and to attempt to identify predictors of and risk factors for progression. Design: Case-control study among employees and comparison of daily clinical features in two groups: infected residents with subsequent development of HUS and those who had no complications. Setting: Two institutions for retarded persons in Utah. Patients: Twenty residents with E. coll O157:H7 infection (13 culture confirmed, 2 probable, and 5 possible); HUS developed in 8, and 4 died. Thirty-one infected employees (3 with culture-confirmed, 6 with probable, and 22 with possible infection). Measurements and main results: In a case-control study among employees, infection was independently assoclated with eating ground beef from a single lot prepared at several barbecues and with close contact with a resident who had diarrhea. Five of eight residents in whom HUS developed had received trimethoprim-sulfamethoxazole, compared with none of seven who had no subsequent complications (p=0.026); this finding may reflect antimicrobial treatment of patients with more severe illness. Compared with infected residents without complications, persons with HUS were younger (median age 13 vs 27 years, p=0.043) and, by the third day of illness, had higher leukocyte counts (median 23.7×109/L vs 9.1×109/L, p=0.018) and temperature (median 38.5°C vs 37.0° C, p=0.016). Leukocytosis peaked on day 4, more than 24 hours before signs of HUS appeared. Conclusions: Food-borne outbreaks of E. coli O157:H7 in insitutions may have devastating effects. Leukocytosis and fever may precede and predict HUS in patients with E. coli O157:H7 infection. © 1990 The C.V. Mosby Company.
