Comparison of virulence gene profiles of Escherichia coli strains isolated from healthy and diarrheic swine

Toni A. Chapman, Xi-Yang Wu, Idris Barchia, Karl A. Bettelheim, Steven Driesen, Darren J. Trott, Mark R. Wilson, James C. Chin

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174 Citations (Scopus)

Abstract

A combination of uni- and multiplex PCR assays targeting 58 virulence genes (VGs) associated with Escherichia coli strains causing intestinal and extraintestinal disease in humans and other mammals was used to analyze the VG repertoire of 23 commensal E. coli isolates from healthy pigs and 52 clinical isolates associated with porcine neonatal diarrhea (ND) and postweaning diarrhea (PWD). The relationship between the presence and absence of VGs was interrogated using three statistical methods. According to the generalized linear model, 17 of 58 VGs were found to be significant (P <0.05) in distinguishing between commensal and clinical isolates. Nine of the 17 genes represented by iha, hlyA, aidA, east1, aah, fimH, iroN(E).(coli), traT, and saa have not been previously identified as important VGs in clinical porcine isolates in Australia. The remaining eight VGs code for fimbriae (F4, F5, F18, and F41) and toxins (STa, STh, LT, and Stx2), normally associated with porcine enterotoxigenic E. coli. Agglomerative hierarchical algorithm analysis grouped E. coli strains into subclusters based primarily on their serogroup. Multivariate analyses of clonal relationships based on the 17 VGs were collapsed into two-dimensional space by principal coordinate analysis. PWD clones were distributed in two quadrants, separated from ND and commensal clones, which tended to cluster within one quadrant. Clonal subclusters within quadrants were highly correlated with serogroups. These methods of analysis provide different perspectives in our attempts to understand how commensal and clinical porcine enterotoxigenic E. coli strains have evolved and are engaged in the dynamic process of losing or acquiring VGs within the pig population.

Original languageEnglish
Pages (from-to)4782-4795
Number of pages14
JournalApplied and Environmental Microbiology
Volume72
Issue number7
DOIs
Publication statusPublished - Jul 2006
Externally publishedYes

Keywords

  • OUTER-MEMBRANE PROTEIN
  • EDEMA DISEASE
  • MULTIPLEX PCR
  • AIDA-I
  • GASTROINTESTINAL-TRACT
  • POSTWEANING DIARRHEA
  • FIMBRIAL ANTIGENS
  • DIFFUSE ADHERENCE
  • PIGS
  • TOXIN

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