An Outbreak of Salmonella Enterica I 4,[5],12:I:- Associated with a Restaurant in Kentucky, 2014

BACKGROUND:   In July 2014, the Kentucky Department for Public Health and local health departments investigated an outbreak of Salmonella entericaI 4,[5],12:i:- cases occurring in the western part of the state. All of the cases reported dining at a restaurant (Restaurant A) prior to becoming ill.    

METHODS:  A case was defined as: Any individual who ate at Restaurant A on or after June 27, 2014 who developed vomiting and/or diarrhea with illness onset of June 27, 2014 or later. Confirmed cases had a laboratory result of Salmonella enterica I 4,[5],12:i:- and exhibited XbaI pattern JPXX01.1192. Kentucky cases were interviewed with a standard foodborne illness questionnaire. Responses were analyzed to identify common exposures and establish a case definition. The Kentucky Division of Laboratory Services serotyped and performed pulsed-field gel electrophoresis (PFGE) analysis on all the clinical isolates available. An environmental assessment was conducted on July 9, 2014 and ten food samples were collected from the restaurant for laboratory analysis via BAX PCR and culture.

RESULTS:  Eleven individuals, 8 Kentucky residents and 3 Illinois residents, were confirmed by PFGE analysis to be connected to the outbreak. An additional 9 Kentucky residents and approximately 33 Illinois residents were epidemiologically-linked to the restaurant, but did not seek medical attention and no laboratory results were available. All but one of the 8 confirmed Kentucky cases and all of the 9 epidemiologically-linked Kentucky cases reported dining at Restaurant A prior to becoming ill. The remaining confirmed case had household exposure to another case who dined at Restaurant A.  The first wave of cases occurred from June 28-July 1.  A second, smaller wave of cases occurred from July 21-July 28. Laboratory testing of the clinical isolates identified Salmonella enterica I 4,[5],12:i:- XbaI pattern JPXX01.1192 as the outbreak pathogen and strain. Five of the food samples yielded XbaI patterns indistinguishable from the clinical isolates. 

CONCLUSIONS:   Unfortunately, information sharing between the states was difficult and only limited information about the Illinois cases could be obtained. Nevertheless, through epidemiologic, environmental, and laboratory investigations, Restaurant A was implicated as the outbreak source. During the environmental investigation, it was noted that the food handlers lacked knowledge of proper food safety procedures and had worked while ill. In the few weeks following the first cases, the restaurant remained open.  After being implicated as the source of the illnesses and the emergence of additional cases, business declined and the restaurant closed.