A one-year longitudinal study of enterohemorrhagic Escherichia coli O157 fecal shedding in a beef cattle herd.
Res Vet Sci
; 127: 27-32, 2019 Dec.
Article
em En
| MEDLINE
| ID: mdl-31670090
ABSTRACT
Bovines are the primary reservoir of enterohemorrhagic Escherichia coli (EHEC) O157H7 and the main source of its transmission to humans. Here, we present a one-year longitudinal study of fecal shedding of E. coli O157. E. coli O157 obtained from recto-anal mucosal samples were characterized by multiplex PCR. The E. coli O157 prevalence ranged from 0.84% in July to 15.25% in November. The confinement within pens resulted in prevalence of 11%. Most animals (61.86%; 75/118) shed E. coli O157 at least in one sampling occasion. Of the positive animals, 82.19%, 16.44%, and 1.37% were stx positive on one, two and three sampling occasions, respectively. All the E. coli O157 isolated strains carried the genes eae and rfbO157, whereas 11%, 33% and 56% contained stx1, stx2 and stx1/stx2, respectively. The stx1/stx2 and stx2 types were significantly higher during the grazing and finishing periods, respectively, in comparison with the rearing and grazing periods. The presence of stx2a subtype was evident in four isolates, whereas stx2c was present in at least seven. However, both subtypes were present simultaneously in two isolates. The stx1/stx2c, stx1/stx2d and stx1/stx2NT genotypes occurred in 24, 2 and 15 isolates, respectively. The simultaneous occurrence of stx1 and stx2c significantly increased during grazing. Some cases of within-pen and between-pen transmission occurred throughout the study. Contagion levels during in-field grazing were higher than during permanent confinement in the pens. Thus, the individual patterns of shedding varied depending on the proportion of animals shedding the bacteria within pens and the time of shedding.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Doenças dos Bovinos
/
Escherichia coli O157
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Infecções por Escherichia coli
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Derrame de Bactérias
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Animals
País/Região como assunto:
America do sul
/
Argentina
Idioma:
En
Revista:
Res Vet Sci
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Argentina