An outbreak of Salmonella gastroenteritis among hospital workers.

Objective. To describe and identify the causes of an outbreak of Salmonella enteritidis gastroenteritis that took place in June 1998, among tertiary c are hospital workers, in Mexico City. Material and methods. Cases were hosp ital workers who developed diarrhea or fever associated with gastrointestin al symptoms, after a meal at the hospital's dining room on June eight; cont rols were asymptomatic employees who also ate at the hospital's dining room on the same day. A food questionnaire was applied, and stool samples were obtained from all study subjects, including kitchen personnel. Blood cultur es were practiced for febrile patients. Odds ratios with 95% confidence int ervals (95% CI) and the chi-squared were used for statistical analysis. Sta tistical significance was set at p < 0.05. Results. One-hundred-fifty-five workers developed symptoms, but only 129 (83.2%) answered the questionnaire ; 150 controls were also studied. The most common symptoms were diarrhea (8 5%), abdominal pain (84%), cephalea (81.4%), nausea (78.3%), and chills (74 .4%). Eight blood cultures were negative; 59 stool cultures (46%) from case s and six (4%) from controls,were positive for Salmonella enteritidis. Egg- covered meat was the suspected source of infection (OR 19.39, 95% CI 9.09-4 1.4); some other foodstuffs like fruit dessert and yogurt, were significant ly more frequent in cases than in controls. Food cultures were all negative . Conclusion. This outbreak was probably caused by Salmonella-contaminated foodstuffs (egg-covered meat with potatoes) due to deficient cooking. This report shows the importance of food-quality programs for hospital meals. Th e English version of this paper is available at: http://www.insp.mx/salud/i ndex.html.