title: Phenotypic characteristics, virulence profile and genetic relatedness of O157 Shiga toxin-producing Escherichia coli isolated in Brazil and other Latin American countries.
abstract: Thirty-eight Shiga toxin-producing Escherichia coli (STEC) O157:H7/H(-) strains isolated from human infections, cattle and foods in Brazil and in some other Latin American countries were compared with regard to several phenotypic and genotypic characteristics. The genetic relatedness of the strains was also determined by pulsed-field gel electrophoresis (PFGE). Similar biochemical behaviour was identified, regardless of the origin and country of the strains. Most (89.5%) strains were sensitive to the antimicrobial agents tested, but resistance to at least one drug was observed among bovine strains. Although a diversity of stx genotypes was identified, most (77.8%) of the human strains harboured stx(2) or stx(2)stx(2c(2vha)), whereas stx(2c(2vha)) prevailed (64.2%) among strains isolated from cattle. stx(1) and stx(1)stx(2c(2vha)) were the genotypes identified less frequently, and occurred exclusively among strains isolated from food and cattle, respectively. Despite differences in the stx genotypes, all strains carried eae-gamma, efa1, ehx, iha, lpf(O157) and toxB sequences. Many closely related subgroups (more than 80% of similarity) were identified by PFGE, and the presence of a particular O157:H7 STEC clone more related to human infections in Brazil, as well as a common origin for some strains isolated from different sources and countries in Latin America can be suggested.
authors.affiliation: Universidade Federal de São Paulo-Escola Paulista de Medicina, Rua Botucatu 862/3 andar, CEP 04023-062 São Paulo, SP, Brazil.
authors.forename: Flávia C
authors.initials: FC
authors.lastname: Bastos
authors.forename: Tânia Mara I
authors.initials: TM
authors.lastname: Vaz
authors.forename: Kinue
authors.initials: K
authors.lastname: Irino
authors.forename: Beatriz Ernestina C
authors.initials: BE
authors.lastname: Guth
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology* / Q000662:veterinary; D019453:Escherichia coli O157 / Q000145:classification* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D006801:Humans; D007843:Latin America / Q000453:epidemiology; D010641:Phenotype; D022603:Shiga Toxins / Q000096:biosynthesis* / Q000235:genetics; D014774:Virulence
chemical_list: D022603:Shiga Toxins