Outbreak of Salmonella braenderup gastroenteritis due to contaminated meatpies: clinical and molecular epidemiology

Objectives To determine the epidemiologic, clinical and molecular character istics of an outbreak of severe gastroenteritis due to the ingestion of mea t pies highly contaminated with Salmonella braenderup. Methods In October 1993, we observed an outbreak of Salmonella braenderup g astroenteritis that occurred in the Lausanne area, Canton de Vaud, Switzerl and. Cultures of suspected food products, of samples at the incriminated fo od factory and from workers, as well as a case-control study, were used to determine the source of the epidemics. Ribotyping of representative Salmone lla braenderup strains was performed to define the molecular epidemiology. The clinical characteristics of this infection were determined by using a s tandardized interview performed during and 6 months after the outbreak in 1 56 of 215 identified patients. Results The outbreak resulted from the ingestion of pies, heavily contamina ted (> 10(6) CFU/g) with a strain of Salmonella braenderup. The contaminati on was due to mishandling and recycling of jelly poured on top of the produ cts. According to its ribotype and plasmid characteristics, this strain had not been isolated previously in Switzerland. Ten of the 24 workers of the incriminated food factory were shedding the epidemic strain in their stools , and one of them reported gastroenteritis 3 weeks before the beginning of the outbreak. The estimated attack rate in the exposed population was 7.5%. The median incubation time was 18 h. Among 127 adult patients studied, 98% had diarrhea, 95% abdominal pain, 74% fever greater than or equal to 38.5 degreesC, 69% nausea and 35% vomiting. One patient developed prosthetic val ve endocarditis, and one reactive arthritis. Long-term complications were n ot identified, although 12 patients complained of irritable bowel syndrome and 24 of unusual asthenia lasting for more than 6 weeks after infection. C hildren had more severe signs and symptoms compared to adults, and six of 2 9 needed hospitalization. Conclusions This study showed that ingestion of food highly contaminated wi th Salmonella braenderup resulted in severe but typical gastroenteritis and indicated mishandling of food during manufacture as the cause of this outb reak.