The risk of the hemolytic-uremic syndrome after antibiotic treatment of Escherichia coli O157 : H7 infections

Background: Children with gastrointestinal infections caused by Escherichia coli O157:H7 are at risk for the hemolytic-uremic syndrome. Whether antibi otics alter this risk is unknown. Methods: We conducted a prospective cohort study of 71 children younger tha n 10 years of age who had diarrhea caused by E. coli O157:H7 to assess whet her antibiotic treatment in these children affects the risk of the hemolyti c-uremic syndrome and to assess the influence of confounding factors on thi s outcome. Estimates of relative risks were adjusted for possible confoundi ng effects with the use of logistic-regression analysis. Results: Among the 71 children, 9 (13 percent) received antibiotics and the hemolytic-uremic syndrome developed in 10 (14 percent). Five of these 10 c hildren had received antibiotics. Factors significantly associated with the hemolytic-uremic syndrome were a higher initial white-cell count (relative risk, 1.3; 95 percent confidence interval, 1.1 to 1.5), evaluation with st ool culture soon after the onset of illness (relative risk, 0.3; 95 percent confidence interval, 0.2 to 0.8), and treatment with antibiotics (relative risk, 14.3; 95 percent confidence interval, 2.9 to 70.7). The clinical and laboratory characteristics of the 9 children who received antibiotics and the 62 who did not receive antibiotics were similar. In a multivariate anal ysis that was adjusted for the initial white-cell count and the day of illn ess on which stool was obtained for culture, antibiotic administration rema ined a risk factor for the development of the hemolytic-uremic syndrome (re lative risk, 17.3; 95 percent confidence interval, 2.2 to 137). Conclusions: Antibiotic treatment of children with E. coli O157:H7 infectio n increases the risk of the hemolytic-uremic syndrome. (N Engl J Med 2000;3 42:1930-6.) (C)2000, Massachusetts Medical Society.