Characterization of Escherichia coli O157:H7 strains isolated from supershedding cattle.
Appl Environ Microbiol
; 79(14): 4294-303, 2013 Jul.
Article
em En
| MEDLINE
| ID: mdl-23645203
ABSTRACT
Previous reports have indicated that a small proportion of cattle shedding high levels of Escherichia coli O157H7 is the main source for transmission of this organism between animals. Cattle achieving a fecal shedding status of 10(4) CFU of E. coli O157H7/gram or greater are now referred to as supershedders. The aim of this study was to investigate the contribution of E. coli O157H7 strain type to supershedding and to determine if supershedding was restricted to a specific set of E. coli O157H7 strains. Fecal swabs (n = 5,086) were collected from cattle at feedlots or during harvest. Supershedders constituted 2.0% of the bovine population tested. Supershedder isolates were characterized by pulsed-field gel electrophoresis (PFGE), phage typing, lineage-specific polymorphism assay (LSPA), Stx-associated bacteriophage insertion (SBI) site determination, and variant analysis of Shiga toxin, tir, and antiterminator Q genes. Isolates representing 52 unique PFGE patterns, 19 phage types, and 12 SBI clusters were obtained from supershedding cattle, indicating that there is no clustering to E. coli O157H7 genotypes responsible for supershedding. While being isolated directly from cattle, this strain set tended to have higher frequencies of traits associated with human clinical isolates than previously collected bovine isolates with respect to lineage and tir allele, but not for SBI cluster and Q type. We conclude that no exclusive genotype was identified that was common to all supershedder isolates.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças dos Bovinos
/
Escherichia coli O157
/
Infecções por Escherichia coli
/
Derrame de Bactérias
Tipo de estudo:
Prevalence_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Animals
País/Região como assunto:
America do norte
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article