title: Use of the espZ gene encoded in the locus of enterocyte effacement for molecular typing of shiga toxin-producing Escherichia coli.
abstract: Infections with Shiga toxin-producing Escherichia coli (STEC) result in frequent cases of sporadic and outbreak-associated enteric bacterial disease in humans. Classification of STEC is by stx genotype (encoding the Shiga toxins), O and H antigen serotype, and seropathotype (subgroupings based upon the clinical relevance and virulence-related genotypes of individual serotypes). The espZ gene is encoded in the locus of enterocyte effacement (LEE) pathogenicity island responsible for the attaching and effacing (A/E) lesions caused by various E. coli pathogens (but not limited to STEC), and this individual gene ( approximately 300 bp) has previously been identified as hypervariable among these A/E pathogens. Sequence analysis of the espZ locus encoded by additional STEC serotypes and strains (including O26:H11, O121:H19, O111:NM, O145:NM, O165:H25, O121:NM, O157:NM, O157:H7, and O5:NM) indicated that distinct sequence variants exist which correlate to subgroups among these serotypes. Allelic discrimination at the espZ locus was achieved using Light Upon eXtension real-time PCR and by liquid microsphere suspension arrays. The allele subtype of espZ did not correlate with STEC seropathotype classification; however, a correlation with the allele type of the LEE-encoded intimin (eae) gene was supported, and these sequence variations were conserved among individual serotypes. The study focused on the characterization of three clinically significant seropathotypes of LEE-positive STEC, and we have used the observed genetic variation at a pathogen-specific locus for detection and subtyping of STEC.
authors.affiliation: National Microbiology Laboratory, 1015 Arlington Street, Winnipeg, Manitoba, Canada. Matthew_Gilmour@phac-aspc.gc.ca
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Gilmour
authors.forename: Dobryan M
authors.initials: DM
authors.lastname: Tracz
authors.forename: Ashleigh K
authors.initials: AK
authors.lastname: Andrysiak
authors.forename: Clifford G
authors.initials: CG
authors.lastname: Clark
authors.forename: Shari
authors.initials: S
authors.lastname: Tyson
authors.forename: Alberto
authors.initials: A
authors.lastname: Severini
authors.forename: Lai-King
authors.initials: LK
authors.lastname: Ng
mesh_terms: D015373:Bacterial Typing Techniques; D001483:Base Sequence; D020895:Enterocytes; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012703:Serotyping; D022603:Shiga Toxins / Q000096:biosynthesis*
chemical_list: D029968:Escherichia coli Proteins; C457340:LEE protein, E coli; D010750:Phosphoproteins; D022603:Shiga Toxins