Shiga toxin 2 overexpression in Escherichia coli O157:H7 strains associated with severe human disease.

Abstract

Variation in disease severity among Escherichia coli O157:H7 infections may result from differential expression of Shiga toxin 2 (Stx2). Eleven strains belonging to four prominent phylogenetic clades, including clade 8 strains representative of the 2006 U.S. spinach outbreak, were examined for stx2 expression by real-time PCR and western blot analysis. Clade 8 strains were shown to overexpress stx2 basally, and following induction with ciprofloxacin when compared to strains from clades 1-3. Differences in stx2 expression generally correlated with Stx2 protein levels. Single-nucleotide polymorphisms identified in regions upstream of stx2AB in clade 8 strains were largely absent in non-clade 8 strains. This study concludes that stx2 overexpression is common to strains from clade 8 associated with hemolytic uremic syndrome, and describes SNPs which may affect stx2 expression and which could be useful in the genetic differentiation of highly-virulent strains.

• Authors: Mahesh Neupane, Galeb S Abu-Ali, Avishek Mitra, David W Lacher, Shannon D Manning, James T Riordan
• Journal: Microbial pathogenesis (Microb Pathog) Vol. 51 Issue 6 Pg. 466-70 (Dec 2011) ISSN: 1096-1208 [Electronic] England
• PMID: 21864671 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2011 Elsevier Ltd. All rights reserved.

Chemical References

• Shiga Toxin 2

Topics

• Cluster Analysis
• Disease Outbreaks
• Escherichia coli Infections (complications, epidemiology, microbiology)
• Escherichia coli O157 (classification, genetics, isolation & purification, pathogenicity)
• Gene Expression
• Hemolytic-Uremic Syndrome (epidemiology, microbiology)
• Humans
• Molecular Typing
• Polymorphism, Single Nucleotide
• Shiga Toxin 2 (biosynthesis)
• Spinacia oleracea (microbiology)
• United States (epidemiology)
• Virulence