A FOODBORNE OUTBREAK OF GASTROENTERITIS INVOLVING 2 DIFFERENT PATHOGENS

On the evening of October 10, 1990, many of the 474 inmates of a state prison in Florida began to experience symptoms of gastroenteritis. An investigation included interviews with inmates, evaluation of the kitchen and food-handling practices, cultures of leftover food, stool cultures, and cultures from the nares and skin lesions of food handlers. Of the 331 inmates interviewed, 215 (65%) had diarrhea, vomiting, or both. The median incubation period was 5 hours (range, 1-41 hours). Cases with onset of illness 8 or more hours after the evening meal were more likely than those with earlier onset to have had only diarrhea without vomiting (p < 0.001). Eating turkey at the evening meal on October 1 0 was associated with risk of illness (relative risk = 4.8, 95% confidence interval 1.7-13.7). Cases who became ill within 8 hours of the evening meal and those who became ill later were both more likely to have eaten turkey than those who did not become ill (p < 0.001 and p < 0.007, respectively). Salmonella infantis and enterotoxin-producing Staphylococcus aureus were both isolated from samples of leftover turkey, and S. infantis was isolated from 18 of 20 stool specimens. Cultures of the anterior nares and skin lesions of food handlers grew S. aureus, but phage typing failed to link these strains to the outbreak. Improper food-handling practices contributed to the development of this outbreak. This report highlights the importance of recognizing multiple-organism outbreaks, since the authors' recommendations for prevention of more cases depended upon knowing the risks associated with the distinct organisms and the possible sources of contamination.