title: Multilocus genotypic characterization of Escherichia coli O157:H7 recovered from food sources.
abstract: Escherichia coli O157:H7 strains (n = 33) recovered from different food sources in Egypt were characterized using molecular assays to identify strain genotypes associated with various levels of pathogenic potential. Genotypic characterization included: lineage-specific polymorphism assay (LSPA-6), Shiga-toxin-encoding bacteriophage insertion site assay (SBI), clade 8 typing, Tir (A255 T) polymorphism, and variant analysis of Shiga toxin 2 gene (Stx 2a and Stx 2c), and anti-terminator Q genes (Q 933 and Q 21). Genotypes LI/II (76%), SBI 1 (60·6%), clade 8 (69·7%), Tir (255 T) (72·7%) and Stx 2c (45·5%) were found to be significantly more frequent compared to other genetic markers in the strains analysed. Multivariable analysis revealed a significant association between LPSA-6 and clade types as well as Tir (A255 T). To the best of our knowledge, this is the first study to report the characterization of these genetic markers in E. coli O157:H7 strains in the Middle East and Africa.
authors.affiliation: Department of Bacteriology,Mycology and Immunology,Faculty of Veterinary Medicine,Mansoura University,Mansoura,Egypt.
authors.forename: M M
authors.initials: MM
authors.lastname: Elhadidy
authors.affiliation: Department of Microbiology & Immunology,Faculty of Pharmacy,Ain Shams University,African Union Organization,St. Abbassia,Cairo,Egypt.
authors.forename: W F
authors.initials: WF
authors.lastname: Elkhatib
mesh_terms: D000818:Animals; D002611:Cheese / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics*; D004534:Egypt; D004927:Escherichia coli Infections / Q000382:microbiology; D019453:Escherichia coli O157 / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics; D005516:Food Microbiology; D016341:Genes, vif / Q000235:genetics; D005838:Genotype; D006801:Humans; D008460:Meat / Q000382:microbiology; D008892:Milk / Q000382:microbiology; D011956:Receptors, Cell Surface / Q000235:genetics; D022621:Shiga Toxin / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D011956:Receptors, Cell Surface; C109287:Tir protein, E coli; D037521:Virulence Factors; D022621:Shiga Toxin
keywords: Characterization; E. coli O157:H7; food; genotypes