Characterization of virulence genes in Escherichia coli strains isolated from pre-weaned calves in the Republic of Korea
Abstract Background Escherichia coli is an important cause of diarrhea in calves and its diarrheagenic properties are related to presence of certain virulence genes. In this study, the prevalence of virulence genes F5 , F17 , F41 , sta , stx1 , stx2 , eae , and saa in E. coli isolated from pre-weane...
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Published in | Acta veterinaria scandinavica Vol. 62; no. 1; pp. 1 - 45 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
London
BioMed Central Ltd
20.08.2020
BioMed Central BMC |
Subjects | |
Online Access | Get full text |
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Summary: | Abstract
Background
Escherichia coli
is an important cause of diarrhea in calves and its diarrheagenic properties are related to presence of certain virulence genes. In this study, the prevalence of virulence genes
F5
,
F17
,
F41
,
sta
,
stx1
,
stx2
,
eae
, and
saa
in
E. coli
isolated from pre-weaned calves presenting with (n= 329) or without diarrhea (n= 360) was explored using multiplex polymerase chain reaction. We also evaluated the association between detection of
E. coli
and the presence of diarrhea.
Results
Escherichia coli
was detected in 56.3% (388/689) of the fecal samples and showed the highest prevalence (66.5%) in 21–40-day-old calves and the lowest (46.3%) among those that were 1–20 days old. The prevalence of the enterotoxigenic
E. coli
(ETEC) and Shiga toxin-producing
E. coli
(STEC) pathotypes was detected in 73.9% and 15.9%, respectively. The results showed no association between diarrhea and the presence of
E. coli
in general, ETEC or STEC. The
F17
gene was the most frequently detected virulence factor in
E. coli
of calves of all ages regardless of diarrhea. Interestingly, the results show that the calves aged 41–60 days with
F17
-positive
E. coli
are at a higher risk for production of Shiga toxin (
Stx1
; 95% confidence intervals: 1.86–31.95; P = 0.005) compared to calves aged 1–20 days; no association between this finding and diarrhea was observed among the calves of this age group. Moreover, the virulence genes associated with the ETEC and STEC strains were not significantly associated with pathogenicity in this study cohort.
Conclusions
These results suggest that while the incidence of
E. coli
is age-related, there was no relationship linking
E. coli
virulence genes to calf age and diarrhea. Furthermore, the present study demonstrated that detection of
E. coli
strains either with or without virulence factors was not associated with diarrhea in pre-weaned calves. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1751-0147 0044-605X 1751-0147 |
DOI: | 10.1186/s13028-020-00543-1 |