Bacillus cereus Food Poisoning Outbreak in a Kindergarten School, Bangkok, Thailand, December 2009

Abstract

On 18 Dec 2009, the Bureau of Epidemiology was notified that 20 students from a private kindergarten school were treated for vomiting and diarrhea. An investigation was conducted to verify the diagnosis, identify source of the outbreak, and implement prevention and control measures. We conducted a descriptive and retrospective cohort study. Medical records at the hospital were reviewed. We also interviewed students, teachers and cooks at the school. A case was a student in this school who developed vomiting with at least one of the followings: fever, diarrhea or abdominal pain from 18 to 22 Dec 2009. Twenty three clinical specimens (vomitus and rectal swabs) and food samples were collected, and sent to National Institute of Health for bacterial culture. Logistic regression was used to determine the food items associated with illness. Symptoms included vomiting (100%), abdominal pain (59%), diarrhea (31%) and fever (26%). Bacillus cereus was isolated from three out of six vomitus specimens as well as the sweet stewed egg and pork served for school lunch on 18 Dec 2009. Thus, this outbreak was due to Bacillus cereus (emetic form) and the common source was likely to be the sweet stewed egg and pork (adjusted OR 2.1, 95% CI 1.0-4.4). To prevent similar outbreaks in the future, people involved in food preparation and serving should emphasize on personal hygiene and sanitary food handling practices. School administrators should exclude symptomatic cooks and food handlers from cooking.