Biology Reference
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US between 1983-2002 include O26 (22%), O111 (16%), O103 (12%), O121
(8%), O45 (7%), and O145 (5%) (
Brooks et al., 2005
).
In Canada, as in the US,
E. coli
O157:H7 is the predominant serotype, caus-
ing 93% of STEC infections (
Pennington, 2010
). Other major serotypes iso-
lated from humans in Canada include O55, O125, O26, O126, O128, and O18
(
Table 5.1
). The incidence of STEC in Canada ranges from 3.0 to 5.3 cases per
100 000, peaking in 1989 and declining thereafter (
CCDR, 1997
). Ground beef
has been the most common source of outbreaks, followed by raw milk, apple
juice, and contaminated water.
In contrast to the North American countries, STEC epidemiology in South
America is marked by a strikingly low incidence of the
E. coli
O157:H7 sero-
type (
Lopez et al., 1995, 1998
;
Aidar-Ugrinovich et al., 2007
). For example,
E. coli
O157:H7 was isolated from 0-18% of STEC cases in Argentina, 9% in
Chile, and none in Uruguay. Common serotypes isolated from HUS and bloody
diarrhea cases include
E. coli
with serotypes O1:NM, O2:NM, O15:H(-),
O25:H(-), O26:H(-), O49:H10, O92:H3, and O11:NM (
Table 5.1
). South
America, specifically Argentina, has an exceptionally high HUS frequency (22
cases per 100,000 children less than 5 years old) (
Lopez et al., 1998
).
STEC infections are a very important public health problem in the UK,
causing 1% of all food poisoning cases in England and Wales and 3% in Scot-
land (
Money et al., 2012
). In the UK, O157:H7 is the most common STEC
serotype; other serotypes of STEC are rarely isolated from human cases.
E. coli
O157:H7 was isolated first in the UK from an outbreak of HUS in 1983 (
Taylor
et al., 1986
). In contrast to the UK, both STEC O157 and non-
E.coli
O157
serotypes are equally important in Continental Europe, especially in Germany
where STEC O157 causes only 30.5% of STEC infections (
Eurosurveillance
Editorial, 2012
). However, compared to the US and the UK, STEC outbreaks
are observed less frequently in Continental Europe. In 2010, a total of 4000
cases were reported in the European Union (EU), with Germany accounting
for 56.8% and the Netherlands accounting for 22.0% (
Eurosurveillance Edito-
rial, 2012
). Common non-
E. coli
O157 serotypes isolated from the EU include
serotypes O26, O111, O103, O128, O91, O113, O2, O9, and O145 (
Pennington,
2010
) (
Table 5.1
). It is important to note that in the EU in 2011, an unusual sero-
type of STEC, O104:H4, caused one of the deadliest known STEC outbreaks
ever recorded (∼3.3% mortality rate). This outbreak originated in Germany in
May 2011 and later spread to most of the countries in Europe. Approximately
4200 cases were identified globally. This outbreak was marked by a strikingly
high rate of HUS (22%) and hemorrhagic colitis (78%) (
Buchholz et al., 2011
;
Rasko et al., 2011
;
Wu et al., 2011
).
The overall yearly rate of STEC infections in Australia is markedly lower
than in North American and European countries: only 0.4 cases per 100,000
between 2000-2010, of which 0.12 was STEC O157 serotype (
Vally et al.,
2012
). Thus, STEC O157 and non-
E.coli
O157 serotypes have been isolated
at similar rates from Australian STEC patients (
Table 5.1
). The predominant
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