Use of signature-tagged mutagenesis to identify genes associated with colonization of sheep by E. coli O157: H7

Nancy A. Cornick, Josh Pitzer, Amy F. Helgerson, Melissa L. Madsen, Kathy L. Kurth, Qianjun Xiao, F. Chris Minion

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Outbreaks of Escherichia coli O157:H7 in the United States due to contaminated foods are a public health issue and a continuing problem. The major reservoir for these organisms is the gastrointestinal tract of ruminants where they are a member of the resident microbiota. Several factors that contribute to the colonization of cattle have been identified, but a systematic screen of genes that might contribute to the colonization and persistence phenotype in mature ruminants has not been reported. Using a sheep model of persistence, signature tagged mutagenesis (STM) was used to screen 1326 mutants for a persistence-negative phenotype of E. coli O157:H7. We identified 9 genes by STM that appeared to be required for colonization and/or survival in sheep. Three of the genes had functions associated with central metabolism (thiK, ftrA and nrdB), one was involved with LPS formation (wbdP), one encodes a non-LEE encoded effector protein (nleB) and one was a methyltransferase encoded on a prophage (Z2389). The remaining three genes did not have homology with any known genes. Six sheep given ΔwbdP and 2 sheep each were given mutants (ΔthiK (Z1745), ΔftrA (Z2164) and Z2389). The ΔwbdP mutant was recovered from the feces of 4/6 sheep at 6 days pi with a mean number of 1.42 log10 CFU/g feces compared to 4.6 log10 CFU/g feces for the wild type strain. This difference was significant (P < 0.001) over the time course of the experiment (days 6–23). Both ΔthiK and ΔftrA mutants were recovered from 1 of 2 sheep at 9 days PI by enrichment procedures (<50 CFU/g feces) whereas mutant Z2389 was not recovered from either animal past 2 days pi. The roles of all of these gene products require further study to determine how the persistence phenotype of a given strain of E. coli O157:H7 interacts with host factors.

Original languageEnglish (US)
Pages (from-to)177-182
Number of pages6
JournalVeterinary Microbiology
Volume201
DOIs
StatePublished - Mar 1 2017
Externally publishedYes

Fingerprint

Escherichia coli O157
mutagenesis
Mutagenesis
Sheep
sheep
Feces
mutants
feces
Genes
genes
Ruminants
Phenotype
phenotype
ruminants
Prophages
Microbiota
methyltransferases
Methyltransferases
food contamination
gastrointestinal system

Keywords

  • Colonization
  • E. coli O157:H7
  • Sheep

ASJC Scopus subject areas

  • Microbiology
  • veterinary(all)

Cite this

Use of signature-tagged mutagenesis to identify genes associated with colonization of sheep by E. coli O157 : H7. / Cornick, Nancy A.; Pitzer, Josh; Helgerson, Amy F.; Madsen, Melissa L.; Kurth, Kathy L.; Xiao, Qianjun; Minion, F. Chris.

In: Veterinary Microbiology, Vol. 201, 01.03.2017, p. 177-182.

Research output: Contribution to journalArticle

Cornick, Nancy A. ; Pitzer, Josh ; Helgerson, Amy F. ; Madsen, Melissa L. ; Kurth, Kathy L. ; Xiao, Qianjun ; Minion, F. Chris. / Use of signature-tagged mutagenesis to identify genes associated with colonization of sheep by E. coli O157 : H7. In: Veterinary Microbiology. 2017 ; Vol. 201. pp. 177-182.
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