A CONTINUING ASSESSMENT OF RISK-FACTORS FOR THE DEVELOPMENT OF ESCHERICHIA-COLI O157-H7-ASSOCIATED HEMOLYTIC-UREMIC SYNDROME

Univariate and multivariate analyses were applied to determine risk fa ctors for the progression of Escherichia coli 0157:H7 enteritis to hem olytic uremic syndrome (HUS). Both clinical and laboratory variables w ere assessed for 118 pediatric patients (28 HUS; 90 enteritis only). V erotoxins 1 and 2 were produced by 89% of E. coli strains whereas vero toxin 2 only was produced by 11%. Although a greater frequency of stra ins producing verotoxin 2 only occurred in HUS isolates (p = 0.11), to xin phenotype was not significantly associated with risk after multiva riate analyses. HUS patients with or without neurological manifestatio ns had similar frequencies of the two toxin phenotypes among their iso lates. Significant associations for young age (RR = 0.984; 95% CI = 0. 971-0.998) and prolonged use of antidiarrheal agents (RR = 44.11; 95% CI = 8.48-229.4) with HUS were apparent. A lesser chance of progressio n was observed for patients whose strains possessed a 4 kb plasmid (RR = 0.27; 95% CI = 0.08-0.94). Our results are consistent with the hypo thesis that progression to HUS is dependent upon both bacterial virule nce factors and the clinical characteristics of the individual patient .