This Article Full Text Full Text (PDF) Supplemental material Other Versions of this Article: AEM.00982-06v1 73/1/22    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Steele, M. Articles by Gannon, V. Search for Related Content PubMed PubMed Citation Articles by Steele, M. Articles by Gannon, V. Agricola Articles by Steele, M. Articles by Gannon, V.

Identification of Escherichia coli O157:H7 Genomic Regions Conserved in Strains with a Genotype Associated with Human Infection ^,

Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada N1G 3W4,¹ Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Lethbridge, Alberta, Canada T1J 3Z4,² Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska 68583-0919³

Received 26 April 2006/ Accepted 9 October 2006

Beta-glucuronidase-negative, sorbitol-nonfermenting isolates of Shiga toxin-producing Escherichia coli O157 comprise part of a clone complex of related enterohemorrhagic E. coli isolates. High-resolution genotyping shows that the O157 populations have diverged into two different lineages that appear to have different ecologies. To identify genomic regions unique to the most common human-associated genotype, suppression subtractive hybridization was used to identify DNA sequences present in two clinical strains representing the human lineage I O157:H7 strains but absent from two bovine-derived lineage II strains. PCR assays were then used to test for the presence of these regions in 10 lineage I strains and 20 lineage II strains. Twelve conserved regions of genomic difference for lineage I (CRD_I) were identified that were each present in at least seven of the lineage I strains but absent in most of the lineage II strains tested. The boundaries of the lineage I conserved regions were further delimited by PCR. Eleven of these CRD_I were associated with E. coli Sakai S-loops 14, 16, 69, 72, 78, 82, 83, 91 to 93, 153, and 286, and the final CRD_I was located on the pO157 virulence plasmid. Several potential virulence factors were identified within these regions, including a putative hemolysin-activating protein, an iron transport system, and several possible regulatory genes. Cluster analysis based on lineage I conserved regions showed that the presence/absence of these regions was congruent with the inferred phylogeny of the strains.

Published ahead of print on 20 October 2006.

Supplemental material for this article may be found at http://aem.asm.org/.

This article has been cited by other articles:

• Ziebell, K., Steele, M., Zhang, Y., Benson, A., Taboada, E. N., Laing, C., McEwen, S., Ciebin, B., Johnson, R., Gannon, V. (2008). Genotypic Characterization and Prevalence of Virulence Factors among Canadian Escherichia coli O157:H7 Strains. Appl. Environ. Microbiol. 74: 4314-4323 [Abstract] [Full Text]  
• Manning, S. D., Motiwala, A. S., Springman, A. C., Qi, W., Lacher, D. W., Ouellette, L. M., Mladonicky, J. M., Somsel, P., Rudrik, J. T., Dietrich, S. E., Zhang, W., Swaminathan, B., Alland, D., Whittam, T. S. (2008). From the Cover: Variation in virulence among clades of Escherichia coli O157:H7 associated with disease outbreaks. Proc. Natl. Acad. Sci. USA 105: 4868-4873 [Abstract] [Full Text]