An outbreak of Salmonella typhimurium phage type 135 infection linked to the consumption of raw shell eggs in an aged care facility.

The first staff member to become ill did not consume the potato pie or rice pudding. Nonetheless, the staff member reported handling and cracking the raw eggs included in the rice pudding. The staff member reported that the exterior surfaces of the shell eggs were visibly contaminated, however, there were no reported breaks in the integrity of the eggshells. A trace-back investigation identified the producer that supplied the nursing home with shell eggs. An environmental investigation identified that whole and crushed grains used to feed the chickens were securely stored, however, an intermediate step, the chicken feed crusher, provided rats with access to crushed grain. Rat faeces were observed in the chicken feed crusher and crushed grain stored in sealed bins. Microbiological sampling of the chicken feed, chicken feed crusher and the exterior surface and interior contents of shell eggs collected after the outbreak were negative for Salmonella spp. However, microbiological sampling of chicken manure from the farm yielded Salmonella Typhimurium phage type 135. This outbreak illustrates the dangers associated with eating inadequately cooked shell eggs. The elderly and immunocompromised persons are particularly susceptible to infection with small numbers of Salmonellae and in turn are more likely to suffer more severe disease than healthy adults. In nursing homes, pasteurised egg products should be used in dishes that are not thoroughly cooked. Hands, cooking utensils and food preparation surfaces should be washed thoroughly after contact with shell eggs to prevent cross contamination. The economic impact of this outbreak was considerable. Three residents were hospitalised and the need for additional staff resources presented an overwhelming burden for the local community. In March 2001, the Communicable Diseases Control Branch and local government investigated an outbreak of gastroenteritis in an aged-care facility in rural South Australia. Initial reports indicated 12 residents and 1 staff member had experienced gastrointestinal illness; 3 residents had been hospitalised. An epidemiological and environmental investigation sought details of illness, food consumption, food purchasing practices and social activities for the 3 day period prior to the onset of illness in the first case. In total, 18 (16 residents, 2 nursing staff) were ultimately linked to this outbreak (Figure). The predominant symptoms were diarrhoea in 18 cases (100%) and vomiting in 10 cases (55.5%). Of the 15 cases for whom the time of onset was available, the median incubation period was 45.5 hours (range: 12 to 94 hours). Thirteen stool specimens provided …