279 - Epidemiological Description of a Shiga toxin-producing Escherichia coli (STEC) Outbreak in Early Learning Centers in a North American Large Urban Setting.

Publication Number: 279.4987

Mohamed M. Eltorki, University of Calgary, Calgary, AB, Canada; Jianling Xie, University of Calgary, Calagary, AB, Canada; Silviu Grisaru, University of Calgary, Calgary, AB, Canada; Francesco (Franco) A. Rizzuti, Alberta Health Services, Calgary, AB, Canada; Kate Snedeker, Alberta Health Services, Calgary, AB, Canada; Phillip I.. Tarr, Washington University in St. Louis School of Medicine, St. Louis, MO, United States; Otto Vanderkooi, University of Calgary, Calgary, AB, Canada; Stephen Freedman, University of Calgary, Calgary, AB, Canada

Background: Shiga toxin (Stx)-producing Escherichia coli (STEC) infections are important human pathogens. In August-September 2023, a central kitchen in Calgary, Canada, which provides food to 11 daycare centers, was the source of the largest daycare centre-associated STEC outbreak ever reported. The outbreak occurred in a health zone that had a standardized approach to care that included laboratory testing every 24-hours to identify the evolution of HUS during its early phase.

Objective: Describe the epidemiology, clinical features, and outcomes of infected children in this outbreak, focusing on healthcare resource utilization and development of hemolytic uremic syndrome (HUS).

Design/Methods: We conducted a retrospective analysis of laboratory-confirmed STEC O157 cases linked to the outbreak. As part of the public health response, stools of all children attending the daycare centers were tested with PCR and/or culture. Data were extracted from provincial electronic records, and connection to the outbreak was determined by public health investigation. Day 0 was defined as the day of stool sample collection.

Results: 359 laboratory-confirmed STEC cases were associated with this outbreak. The pathogen was a STEC O157:H7 (Stx 1 and Stx 2 positive). Data from 238 infected children and 35 infected adults are included in this analysis. Median age of infected children was 3.3 (IQR 2.3, 4.2) years. 34 (14%) infected children were hospitalized, and 19 (8%) developed HUS, 8 (42%) of whom required renal replacement therapy; there were no deaths. Within 7 days of Day 0 of the first case, 206 children were diagnosed and 30 were hospitalized. Symptoms on day 0 included diarrhea (92%), abdominal pain (74%), hematochezia (61%), vomiting (36%), and fever (36%). Medications administered before specimen collection included acetaminophen (61%), NSAIDs (22%), narcotics (9%), antidiarrheals (5%), and antibiotics (3%). 38% of admissions occurred at the index visit, while the remaining admissions took place a median of 48 hours later (IQR: 42–96 hours). Among children who developed HUS, 10 (53%) were admitted on Day 0 and 9 were admitted at subsequent visits. Of the HUS cases admitted at follow-up visits, 44% (4/9) presented without symptoms (e.g., petechiae, pallor, anuria, edema, jaundice, tea-colored urine) indicative of microangiopathy or HUS progression.

Conclusion(s): This STEC daycare outbreak, with all cases contracted in a single city, represents a unique event. Early detection of cases and standardization of care were critical in identifying those with evolving HUS, and in mitigating adverse outcomes.

Number of cases diagnosed with Shiga toxin-producing Escherichia coli during the outbreak, hospitalized to the inpatient ward or the paediatric intensive care unit
Figure day0 and admissions.pdf

Cumulative and daily admissions of children diagnosed with Shiga toxin-producing Escherichia coli during the outbreak, to pediatric inpatient ward and intensive care unit
Figure admission.pdf