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The genus Yersinia is
a member of the Enterobacteriaceae family that includes eleven species. Y
enterocolitica is most important as a cause of foodborne
illness. Yersinia enterocolitica is a small pleomorphic gram-negative,
non-spore-forming coccobacillus. The organism has been classified
into 6 biotypes and into more than 60 serotypes. The serotypes most
often associated with human disease are 0:3, 0:5, 0:8, 0:9, 0:13,
and 0:27. Human illness can occur after consumption of Y
enterocolitica-contaminated food, animal waste, and unchlorinated
water.1,2This organism may survive and grow during
refrigerated storage.
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The organism has
a large animal reservoir, including cattle, sheep, swine, dogs,
cats, horses, rodents, and lagomorphs. Streams, lakes, and drinking
water have all been contaminated.
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Yersinia enterocolitica has been isolated from
humans worldwide, but most commonly in cooler climates. The organism
has a large animal reservoir, including cattle, sheep, swine, dogs,
cats, horses, rodents, and lagomorphs. Streams, lakes, and drinking
water have all been contaminated. The most common mode of transmission
is ingestion of contaminated food, milk, or water.3 Occasional outbreaks
have been reported within families or institutions. Common source
outbreaks have been traced to raw milk, contaminated pasteurized
milk, and foods prepared with contaminated water. Person-to-person
transmission has not been conclusively proven but probably occurs.
Seasonal isolation rates of Yersinia indicate that
it is more prevalent as a cause of enteritis in winter months in
the United States.4,5 Most reported cases have
been from Canada, Europe, and the United States. Clustering of infections
during fall and winter has been reported in northern Europe.1 Because
pigs are often infected, persons who eat or handle pork are at risk
of getting infected. Diarrheal illness in infants caused by Y
enterocolitica 0:3 in the United States is associated with
household preparation of raw pork intestines (chitterlings).6 In
one study 20 (62%) of 32 children with Y enterocolitica diarrheal
illness had been exposed to raw pork intestines in the 2 weeks before
onset. Affected infants were probably exposed to infection by their caretakers
who were cleaning the chitterlings while caring for the infants.African
American infants have the highest incidence of infection in the
United States.7 Among 142 pediatric patients with Y
enterocolitica enteritis, 141 were black, 85% were
under age 1, and 84 presented during November to January.7 Rarely,
severe infections have been transmitted from blood transfusions.8 Some
blood donors may occasionally have transient occult Y enterocolitica bacteremia
at the time of donation, and the organism can multiply to high concentrations in
refrigerated blood. One instance of perinatal transmission has been
reported.
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The frequency of isolation of Y enterocolitica from
stools of patients with diarrhea is reported to be 1% to
3% in a number of studies. In one Canadian report, it was
recovered in 2.8% of stool cultures from 6364 children
with diarrheal illnesses over a 15-month period. It was isolated
less often than Salmonella, but more commonly ...