Restaurant Salmonella enteritidis outbreak associated with an
asymptomatic infected food worker

01.nov.09
Journal of Food Protection(r), Volume 72, Number 11, pp. 2332-2336(5)
Hedican, Erin; Hooker, Carol; Jenkins, Timothy; Medus, Carlota; Jawahir,
Selina; Leano, F.e.; Smith, Kirk

Abstract:
Salmonella is the most common bacterial cause of foodborne outbreaks in
the United States; approximately half of Salmonella outbreaks occur in
restaurant settings. In February 2008, investigation of a cluster of
Salmonella Enteritidis cases with indistinguishable pulsed-field gel
electrophoresis (PFGE) patterns revealed that five cases had eaten at
the same restaurant. Cases were identified through routine surveillance
activities and by contacting meal companions of culture-confirmed cases.
Well meal companions and well patrons contacted via check stubs served
as controls. Illness histories and stool samples were collected from all
restaurant employees. Sandwiches were the only menu item or ingredient
significantly associated with illness (15 of 15 cases versus 17 of 37
controls; odds ratio, undefined; P < 0.001). None of the six restaurant
employees reported experiencing recent gastrointestinal symptoms. The
outbreak PFGE subtype of Salmonella Enteritidis was identified in two
food workers. One of the positive employees began working at the
restaurant shortly before the first exposure date reported by a case,
and assisted in the preparation of sandwiches and other foods consumed
by cases. The other positive employee rarely, if ever, handled food. The
restaurant did not have a glove use policy. There was no evidence of
ongoing transmission after exclusion of the positive food workers. This
was a restaurant Salmonella Enteritidis outbreak associated with an
asymptomatic infected food worker. Routine PFGE subtyping of Salmonella
Enteritidis isolates, routine interviewing of cases, and an iterative
approach to cluster investigations allowed for timely identification of
the source of an outbreak of Salmonella Enteritidis infections.
Document Type: Research article
Affiliations: 1: Acute Disease Investigation and Control Section,
Minnesota Department of Health, 625 Robert Street N., P.O. Box 64975,
St. Paul, Minnesota 55164-0975;, Email: erin.hedican@state.mn.us
2:
Hennepin County Public Health Protection, 1101 South First Street,
Hopkins, Minnesota 55343-9413 3: Division of Environmental Health, City
of Minneapolis, 250 South 4th Street, Minneapolis, Minnesota 55415-1391,
USA 4: Acute Disease Investigation and Control Section, Minnesota
Department of Health, 625 Robert Street N., P.O. Box 64975, St. Paul,
Minnesota 55164-0975 5: Public Health Laboratory, Minnesota Department
of Health, 625 Robert Street N., P.O. Box 64975, St. Paul, Minnesota
55164-0975