Salmonella enteritidis Gastroenteritis Transmitted by Intact Chicken Eggs

Abstract

▪ Objective: To determine the source and to describe the clinical importance of a large outbreak of Salmonella enteritidis gastroenteritis in Tennessee, which is outside the geographic focus of the S. enteritidis pandemic.

▪ Design: A case-control study and tracing of the source eggs.

▪ Setting: A Tennessee community and a large layer farm in Indiana.

▪ Patients: Case patients ate at the implicated restaurant and subsequently developed S. enteritidis gastroenteritis; controls ate with the case patients, but did not develop gastroenteritis.

▪ Measurements: Eighty-one case patients were identified; 73 (90%) had eaten egg-containing sauces at a local restaurant on a given evening. The eggs were traced to their farm of origin in Indiana. The farm was inspected 5 weeks after the outbreak.

⅖ Main Results: Of 24 patients with culture-proved cases, 11 were hospitalized. Hollandaise and bernaise sauces prepared with intact, extra-large, grade-A eggs were strongly associated with illness (P < 0.001). Salmonella enteritidis was isolated from specimens collected from chickens and the farm. Antimicrobial susceptibility patterns, phage typing, and plasmid profiles of isolates from the farm and from patients were indistinguishable.

▪ Conclusions: Salmonella enteritidis infection is a large and growing public health problem that is spreading beyond the northeastern United States. This study shows a direct link between infected poultry flocks and an outbreak of human illness.