Predicting progression of STEC-HUS: Use of Shiga toxin subtype and routine laboratory screening.

Background: Hemolytic uremic syndrome (HUS) is life-threatening sequelae of Shiga toxin producing Escherichia coli (STEC) enteric infection. To address ambiguity in medical literature, we aimed to identify which STEC toxin profiles and clinical variables were at highest risk of HUS progression to inform evidence-based screening guidelines.

Methods: This was a 5-year retrospective study of children aged <18 years with E. coli O157, Shiga toxin 1 (stx1), or Shiga toxin 2 (stx2)-positive stool. Demographics, clinical symptoms, laboratory studies, and HUS progression were abstracted from the electronic health record. Univariate and multivariable logistic regression identified variables associated with HUS.

Results: Of 1,071 children with STEC, 55 were hospitalized with HUS (mean age 4.4 years [SD 3.7]). Predictors of HUS were age < 5 years and stool positive for E. coli O157 with stx2, or non-O157 stx2. No children of any age with O157 alone, O157 and stx1, or non-O157 stx1 and stx2 developed HUS. The prevalence of HUS with non-O157 stx1 alone was 0.2%.  Vomiting, dehydration, abnormal blood counts and chemistry were the only clinical variables associated with HUS.

Conclusion: We urge care management guidelines based on E. coli serotype and stx. All families of children with STEC should be counseled on the signs and symptoms of HUS and the steps to prevent dehydration; however, serial laboratory monitoring for HUS screening can be reserved for children at highest risk for HUS. Given the substantial differences in HUS risk with stx2 as the main driver of HUS, we advocate that laboratories provide stx results to better inform anticipatory guidance. .