Epidemiology and Infection

Table of Contents - July 2011 - Volume 139, Issue 07  

E. coli O157

Microarray-based detection of virulence genes in verotoxigenic Escherichia coli O157:H7 strains from Swedish cattle

R. SÖDERLUNDa1 c1, A. ASPÁNa1, R. M. LA RAGIONEa2, E. ERIKSSONa1 and S. BOQVISTa3

a1 National Veterinary Institute, Uppsala, Sweden

a2 Department for Food and Environmental Safety, Veterinary Laboratories Agency, Addlestone, Surrey, UK

a3 Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden

SUMMARY

Verotoxigenic Escherichia coli (VTEC) serotype O157:H7 strains from a Swedish cattle prevalence study (n=32), and livestock-derived strains linked to human disease (n=13), were characterized by microarray and PCR detection of virulence genes. The overall aim of the study was to investigate the distribution of known virulence determinants and determine which genes are linked to increased pathogenicity in humans. A core set of 18 genes or gene variants were found in all strains, while seven genes were variably present. This suggests that the majority of VTEC O157:H7 found in Swedish cattle carry a broad repertoire of virulence genes and should be considered potentially harmful to humans. A single virulence gene type was significantly associated with strains linked to human disease cases (P=0·012), but no genetic trait to explain the increased virulence of this genotype could be found.

(Accepted August 06 2010)

(Online publication September 15 2010)

Key Words:

Correspondence:

c1 Author for correspondence: Mr R. Söderlund, BKT, Statens Veterinärmedicinska Anstalt, 75189 Uppsala, Sweden. (Email: robert.soderlund@sva.se)

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