Biology Reference
In-Depth Information
Chapter 27
Prevalence of Verocytotoxin-Producing E. coli
in Sheep Meat at a Slaughterhouse
R. Mazzette, A. Mureddu, G. Busia, R. Mazza, S. Lamon, and D. Meloni
Abstract Sheep play important roles in the spread of pathogenic
Escherichia coli
that can cause severe diseases in humans. The aim of the present study was to
evaluate the prevalence of verocytotoxin-producing
E. coli
(VTEC) in various
samples from Sarda sheep using a molecular screening test and to define the
virulence profiles of isolates using multiplex PCR. A total of 380 different ovine
samples (fleece, carcass surface, and mucosal gut) were analyzed by direct PCR
screening for the presence of
stx
1
e
stx
2
genes. Virulence factors (
stx
1
,
stx
2
, and
eae
)
from the strains, isolated by immunomagnetic separation (IMS)-based cultivation
techniques (e.g., CT-SMAC, CT-RMAC, and EHLY agar), were determined by
multiplex PCR. An overall prevalence of 11.1% (adults 14%, lambs 7.8%) was
found by direct PCR. VTEC occurrence was 18.9% in fleece, 14.7% on carcasses,
and 10.5% in mucosal gut. According to the multiplex-PCR results, the following
values were obtained: 43.4% VTEC (
stx
1
,
stx
2
,
stx
1
þ
stx
2
,
stx
2
þ
eae
, and
stx
1
þ
stx
2
þ
eae
), 30.3% EPEC (
stx
1
-/
stx
2
-/
eae
+), and 26.4% negative for all genes
examined (
stx
1
-,
stx
2
-,
eae
-).
Keywords
E. coli
• PCR • Sheep • VTEC
27.1
Introduction
Verocytotoxin (VT)-producing
Escherichia coli
(VTEC) are zoonotic agents that
cause a potentially fatal human illness; its clinical spectrum includes diarrhea,
hemorrhagic colitis (HC), and hemolytic-uremic syndromes (HUS) (Karmali
et al.
2010
). The presence of VTEC in foods is a serious public health concern
R. Mazzette (
*
) • A. Mureddu • G. Busia • R. Mazza • S. Lamon • D. Meloni
Dipartimento di Biologia Animale, Sezione Ispezione degli Alimenti, Facolt` di Medicina
Veterinaria, Universit` di Sassari, Sassari, Italy
e-mail:
rmazzett@uniss.it
