The DNA sequence of the Escherichia coli O22 O-antigen gene cluster and detection of pathogenic strains belonging to E. coli serogroups O22 and O91 by multiplex PCR assays targeting virulence genes and genes in the respective O-antigen gene clusters

Pina M. Fratamico, Chitrita Debroy, Yanhong Liu

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Multiplex polymerase chain reaction (PCR) assays were developed for detection of pathogenic strains belonging to Escherichia coli serogroups O22 and O91. The O-antigen gene cluster of E. coli O22 was sequenced to identify genes that could be employed as targets for serogroup-specific PCR assays. The wzx and wzy genes in the O-antigen gene clusters of E. coli O22 and E. coli O91 were selected as target genes. The assays were serogroup-specific when tested against 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, humans, and animals, representative strains belonging to 168 E. coli O serogroups and non-E. coli bacteria. Furthermore, 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, water, animals, and humans were tested by the PCR for the presence of six and 19 virulence genes, respectively, associated with pathogenic E. coli strains. Based on the PCR screening results, multiplex PCR assays targeting the O22 wzy gene and the cnf-1 and sfa genes in E. coli O22 and the O91 wzy gene, conserved sequences of stx 1 and stx 2 genes, and the astA and cdt-III genes in E. coli O91 were developed to detect and identify pathogenic strains belonging to serogroups O22 and O91. Furthermore, E. coli O22 and O91 were detected by multiplex PCR assays targeting the wzx or wzy genes and conserved sequences of the stx 1 and stx 2 genes in ground beef samples inoculated with approximately two colony-forming units (CFU)/25 g after 18-h enrichment. The results demonstrate that the E. coli O22 and O91 wzx and wzy gene sequences were specific for the respective serogroups and can be used as diagnostic markers for rapid identification of these serogroups as an alternative to serotyping. The multiplex PCR assays targeting the O22 and O91 wzx and wzy genes and virulence genes can be used to identify and to detect pathogenic strains of these serogroups in food and fecal samples.

Original languageEnglish (US)
Pages (from-to)169-179
Number of pages11
JournalFood Analytical Methods
Volume2
Issue number3
DOIs
StatePublished - Oct 15 2009

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O Antigens
Gene Targeting
Multiplex Polymerase Chain Reaction
Polymerase chain reaction
DNA sequences
Antigens
Multigene Family
multigene family
Escherichia coli
Virulence
Assays
serotypes
virulence
Genes
polymerase chain reaction
antigens
nucleotide sequences
assays
genes
food

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Food Science
  • Applied Microbiology and Biotechnology
  • Safety, Risk, Reliability and Quality
  • Safety Research

Cite this

@article{e5bea2809a6f4424863999057bc3141d,
title = "The DNA sequence of the Escherichia coli O22 O-antigen gene cluster and detection of pathogenic strains belonging to E. coli serogroups O22 and O91 by multiplex PCR assays targeting virulence genes and genes in the respective O-antigen gene clusters",
abstract = "Multiplex polymerase chain reaction (PCR) assays were developed for detection of pathogenic strains belonging to Escherichia coli serogroups O22 and O91. The O-antigen gene cluster of E. coli O22 was sequenced to identify genes that could be employed as targets for serogroup-specific PCR assays. The wzx and wzy genes in the O-antigen gene clusters of E. coli O22 and E. coli O91 were selected as target genes. The assays were serogroup-specific when tested against 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, humans, and animals, representative strains belonging to 168 E. coli O serogroups and non-E. coli bacteria. Furthermore, 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, water, animals, and humans were tested by the PCR for the presence of six and 19 virulence genes, respectively, associated with pathogenic E. coli strains. Based on the PCR screening results, multiplex PCR assays targeting the O22 wzy gene and the cnf-1 and sfa genes in E. coli O22 and the O91 wzy gene, conserved sequences of stx 1 and stx 2 genes, and the astA and cdt-III genes in E. coli O91 were developed to detect and identify pathogenic strains belonging to serogroups O22 and O91. Furthermore, E. coli O22 and O91 were detected by multiplex PCR assays targeting the wzx or wzy genes and conserved sequences of the stx 1 and stx 2 genes in ground beef samples inoculated with approximately two colony-forming units (CFU)/25 g after 18-h enrichment. The results demonstrate that the E. coli O22 and O91 wzx and wzy gene sequences were specific for the respective serogroups and can be used as diagnostic markers for rapid identification of these serogroups as an alternative to serotyping. The multiplex PCR assays targeting the O22 and O91 wzx and wzy genes and virulence genes can be used to identify and to detect pathogenic strains of these serogroups in food and fecal samples.",
author = "Fratamico, {Pina M.} and Chitrita Debroy and Yanhong Liu",
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T1 - The DNA sequence of the Escherichia coli O22 O-antigen gene cluster and detection of pathogenic strains belonging to E. coli serogroups O22 and O91 by multiplex PCR assays targeting virulence genes and genes in the respective O-antigen gene clusters

AU - Fratamico, Pina M.

AU - Debroy, Chitrita

AU - Liu, Yanhong

PY - 2009/10/15

Y1 - 2009/10/15

N2 - Multiplex polymerase chain reaction (PCR) assays were developed for detection of pathogenic strains belonging to Escherichia coli serogroups O22 and O91. The O-antigen gene cluster of E. coli O22 was sequenced to identify genes that could be employed as targets for serogroup-specific PCR assays. The wzx and wzy genes in the O-antigen gene clusters of E. coli O22 and E. coli O91 were selected as target genes. The assays were serogroup-specific when tested against 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, humans, and animals, representative strains belonging to 168 E. coli O serogroups and non-E. coli bacteria. Furthermore, 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, water, animals, and humans were tested by the PCR for the presence of six and 19 virulence genes, respectively, associated with pathogenic E. coli strains. Based on the PCR screening results, multiplex PCR assays targeting the O22 wzy gene and the cnf-1 and sfa genes in E. coli O22 and the O91 wzy gene, conserved sequences of stx 1 and stx 2 genes, and the astA and cdt-III genes in E. coli O91 were developed to detect and identify pathogenic strains belonging to serogroups O22 and O91. Furthermore, E. coli O22 and O91 were detected by multiplex PCR assays targeting the wzx or wzy genes and conserved sequences of the stx 1 and stx 2 genes in ground beef samples inoculated with approximately two colony-forming units (CFU)/25 g after 18-h enrichment. The results demonstrate that the E. coli O22 and O91 wzx and wzy gene sequences were specific for the respective serogroups and can be used as diagnostic markers for rapid identification of these serogroups as an alternative to serotyping. The multiplex PCR assays targeting the O22 and O91 wzx and wzy genes and virulence genes can be used to identify and to detect pathogenic strains of these serogroups in food and fecal samples.

AB - Multiplex polymerase chain reaction (PCR) assays were developed for detection of pathogenic strains belonging to Escherichia coli serogroups O22 and O91. The O-antigen gene cluster of E. coli O22 was sequenced to identify genes that could be employed as targets for serogroup-specific PCR assays. The wzx and wzy genes in the O-antigen gene clusters of E. coli O22 and E. coli O91 were selected as target genes. The assays were serogroup-specific when tested against 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, humans, and animals, representative strains belonging to 168 E. coli O serogroups and non-E. coli bacteria. Furthermore, 72 E. coli O22 strains and 57 E. coli O91 strains isolated from food, water, animals, and humans were tested by the PCR for the presence of six and 19 virulence genes, respectively, associated with pathogenic E. coli strains. Based on the PCR screening results, multiplex PCR assays targeting the O22 wzy gene and the cnf-1 and sfa genes in E. coli O22 and the O91 wzy gene, conserved sequences of stx 1 and stx 2 genes, and the astA and cdt-III genes in E. coli O91 were developed to detect and identify pathogenic strains belonging to serogroups O22 and O91. Furthermore, E. coli O22 and O91 were detected by multiplex PCR assays targeting the wzx or wzy genes and conserved sequences of the stx 1 and stx 2 genes in ground beef samples inoculated with approximately two colony-forming units (CFU)/25 g after 18-h enrichment. The results demonstrate that the E. coli O22 and O91 wzx and wzy gene sequences were specific for the respective serogroups and can be used as diagnostic markers for rapid identification of these serogroups as an alternative to serotyping. The multiplex PCR assays targeting the O22 and O91 wzx and wzy genes and virulence genes can be used to identify and to detect pathogenic strains of these serogroups in food and fecal samples.

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