A hospital acquired outbreak of Bacillus cereus gastroenteritis, Oman

To investigate the course of a hospital acquired outbreak of Bacillus cereus gastroenteritis outbreak, and the interventions that were taken to prevent such an outbreak from occurring again.

On May 3-5 2008, 58 cases of gastroenteritis were reported among patients and their attendants in a referral hospital in Oman. All affected had eaten meals served by the hospital kitchen the previous day. An outbreak investigation team conducted active surveillance and interviewed people about symptoms and food consumed on the preceding day in the hospital. Food samples from the kitchen and faecal samples from the kitchen staff and those affected were cultured. An environmental audit of the kitchen was conducted.

The majority of the 58 persons affected by the outbreak were adult females, predominantly attendants of patients. 90% had diarrhoea and 10% had vomiting, usually mild. All those affected were managed symptomatically except for two patient attendants who required intravenous rehydration. The meal exposure histories implicated at least one meal from the kitchen. Many violations of basic food hygiene standards were observed in the kitchen. Toxin producing B. cereus was isolated from faeces of 3/12 (25%) patients and 19/25 (76%) of food handlers, and 35/61 (57%) of food samples from the kitchen.

This is the first report of a nosocomial outbreak of foodborne B. cereus infection from this region. The importance of appropriate epidemiological and microbiological investigation and public relations management is emphasized, in addition to the need for continuing training of food handlers and rigorous enforcement of food hygiene regulations.