title: Characterization of Shiga toxin-producing Escherichia coli O157:H7 isolated in Italy and in France.
abstract: Twenty-one Escherichia coli O157:H7 strains isolated in northern Italy from sporadic cases of hemolytic-uremic syndrome and from cattle and food were characterized by virulence gene analysis, pulsed-field gel electrophoresis (PFGE) of XbaI-digested DNA, enterobacterial repetitive intergenic consensus (ERIC) sequence-based PCR (ERIC-PCR), and antibiotic resistance patterns and compared to 18 strains isolated in France from human cases of diarrhea, cattle, and the environment. Strains isolated in Sicily (southern Italy) from a local farm (one strain) and from calves just imported from France (11 strains) and Spain (six strains) were also typed. Whereas the eae and hlyA genes were always detected, Shiga toxin gene (stx) analysis showed some differences related to geographic areas. Isolates from northern Italy showed a high frequency of stx(1) and stx(2), while strains isolated in France and from French and Spanish calves imported to Sicily more frequently possessed the stx(2c) gene. The majority of the strains isolated in northern Italy were also resistant to one or more antibiotics, while most of the strains isolated in France and Sicily were fully susceptible. ERIC-PCR analysis was not able to differentiate the strains. PFGE typing after XbaI DNA digestion produced a total of 54 distinct restriction endonuclease digestion profiles (REDPs) among the 57 strains. Phylogenetic analysis was unable to cluster REDPs according to geographic origin. All epidemiologically related isolates showed either identical or >/=91% similar REDPs. Our findings suggest a peculiar circulation of antibiotic-resistant, genetically unrelated strains in northern Italy.
authors.affiliation: Dipartimento di Igiene e Microbiologia, Università di Palermo, I-90127 Palermo, Italy. gmgiamm@libero.it
authors.forename: Giovanni M
authors.initials: GM
authors.lastname: Giammanco
authors.forename: Sarina
authors.initials: S
authors.lastname: Pignato
authors.forename: Francine
authors.initials: F
authors.lastname: Grimont
authors.forename: Patrick A D
authors.initials: PA
authors.lastname: Grimont
authors.forename: Alfredo
authors.initials: A
authors.lastname: Caprioli
authors.forename: Stefano
authors.initials: S
authors.lastname: Morabito
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giammanco
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D002648:Child; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000662:veterinary; D019453:Escherichia coli O157 / Q000145:classification* / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity; D005602:France; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology*; D006801:Humans; D007558:Italy; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D022622:Shiga Toxin 1 / Q000096:biosynthesis*; D022641:Shiga Toxin 2 / Q000096:biosynthesis*; D014774:Virulence / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2