This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Baker, D. R.
Right arrow Articles by Francis, D. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Baker, D. R.
Right arrow Articles by Francis, D. H.
Agricola
Right arrow Articles by Baker, D. R.
Right arrow Articles by Francis, D. H.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, November 2007, p. 7338-7346, Vol. 73, No. 22
0099-2240/07/$08.00+0     doi:10.1128/AEM.00755-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Differences in Virulence among Escherichia coli O157:H7 Strains Isolated from Humans during Disease Outbreaks and from Healthy Cattle{triangledown}

Diane R. Baker,1 Rodney A. Moxley,2 Mike B. Steele,1 Jeffrey T. LeJeune,3 Jane Christopher-Hennings,1 Ding-Geng Chen,4 Philip R. Hardwidge,1 and David H. Francis1*

Department of Veterinary Science, South Dakota State University, Brookings, South Dakota,1 Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska,2 Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Ohio State University, Wooster, Ohio,3 Department of Mathematics and Statistics, South Dakota State University, Brookings, South Dakota4

Received 4 April 2007/ Accepted 10 September 2007

Escherichia coli O157:H7 causes life-threatening outbreaks of diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome in humans and significant economic loss in agriculture and could be a potential agent of bioterrorism. Although the prevalence of E. coli O157:H7 in cattle and other species with which humans have frequent contact is high, human infections are relatively uncommon, despite a low infectious dose. A plausible explanation for the low disease incidence is the possibility that not all strains are virulent in humans. If there are substantial differences in virulence among strains in nature, then human disease may select for high virulence. We used a gnotobiotic piglet model to investigate the virulence of isolates from healthy cattle and from humans in disease outbreaks and to determine the correlation between production of Shiga toxin 1 (Stx1) and Stx2 and virulence. Overall, E. coli O157:H7 strains isolated from healthy cattle were less virulent in gnotobiotic piglets than strains isolated from humans during disease outbreaks. The amount of Stx2 produced by E. coli O157:H7 strains correlated with strain virulence as measured by a reduction in piglet survival and signs of central nervous system disease due to brain infarction. The amount of Stx1 produced in culture was not correlated with the length of time of piglet survival or with signs of central nervous system disease. We suggest that disease outbreaks select for producers of high levels of Stx2 among E. coli O157:H7 strains shed by animals and further suggest that Stx1 expression is unlikely to be significant in human outbreaks.

* Corresponding author. Mailing address: Veterinary Science Department, South Dakota State University, Box 2175, 1119 North Campus Drive, Brookings, SD 57007. Phone: (605) 688-5680. Fax: (605) 688-6003. E-mail: david.francis{at}sdstate.edu

{triangledown} Published ahead of print on 21 September 2007.

Applied and Environmental Microbiology, November 2007, p. 7338-7346, Vol. 73, No. 22
0099-2240/07/$08.00+0     doi:10.1128/AEM.00755-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Lowe, R. M. S., Baines, D., Selinger, L. B., Thomas, J. E., McAllister, T. A., Sharma, R. (2009). Escherichia coli O157:H7 Strain Origin, Lineage, and Shiga Toxin 2 Expression Affect Colonization of Cattle. Appl. Environ. Microbiol. 75: 5074-5081 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»