E. coli O157:H7 outbreak and hemolytic uremic syndrome in a day care center in Brazil

Abstract

Background: Shiga toxin-producing Escherichia coli O157:H7 (STEC-O157: H7) infection is related to major outbreaks and serious diseases such as hemolytic uremic syndrome (HUS). In March 2019, a gastroenteritis outbreak occurred in the day care center of Vila Velha-Brazil, and a death occurred by HUS. Epidemiological investigation was conducted to identify the agent involved and source of infection. Methods and materials: A descriptive study. Cases were: children or employees who presented diarrhea or vomiting from March 1st to April 5th, 2019. A semi-structured questionnaire was applied. The rate attack of cases per class was calculated. Stool samples were collected from the cases and from water reservoir, kitchen tap reducer, water toy, water and food. Laboratory techniques used: culture, Polymerase chain reaction (PCR), and pulsed field electrophoresis- PFGE. Results: There were 24 cases of diarrhea, of these two (79,0%) were children, five (20,9%) employees. The cases reduced by 92% after the suspension of day care activities in March 26th. The 2-year-old class had the highest attack rate (40,0%) and there were no case in the 4-year-old class. Bloody diarrhea was reported in five (21,0%), abdominal pain nine (38,0%), vomiting eight (33,0%), and three (12,0%) evolved to HUS, with one death (33% lethality by SHU). STEC-O157: H7 was detected in two children who had bloody diarrhea (one with HUS) and in the water tap reducer. The PFGE analysis identified that, the genetic homology between case strains was 90% and the genetic similarity between the cases and the water tap reducer was 64,0%. Conclusion: A gastroenteritis outbreak occurred in the day care center involving the EHEC O157: H7 strain. It is suggested that E. coli was introduced into the day care center by an infected person, spreading the outbreak, maintained by person-to-person transmission, stop the school activities and professionals guide about the characteristics of the disease helped in minimizing the severity of cases. It was recommended to guide teachers/staff about how to prevent fecal-oral transmission diseases, and to monitor water quality in the day care center.