GIS-supported investigation of a nosocomial Salmonella outbreak

Within an outbreak at a university hospital 102 persons (44 patients, 26 nursery school children and one relative as well as 31 employees) have been diagnosed to be infected by Salmonella enteritidis. Ninety-nine persons complied with the "primary case"-definition. The source of infection could not be detected in retrospect by hygienic-microbiological methods due to missing food samples. But GIS (Geographical Information System)-supported epidemiological investigation and analysis of food production showed that most likely vanilla pudding had been the vehicle of infection. Contamination of the pudding could be put down to the fact that its production took place in direct spatial and temporal association with the preparation of turkey. Probably further infections caused by this primary source were avoided by immediate measures. The making out of an HACCP-concept as well as structural and technical short-term redevelopment measures proved to be decisive factors to decrease the risk of further infections. From these experiences, some recommendations could be derived for the investigation of food-borne outbreaks in hospitals.