title: Diversity of Shiga toxin-producing Escherichia coli in sheep flocks of Paraná State, southern Brazil.
abstract: Sheep constitute an important source of zoonotic pathogens as Shiga toxin-producing Escherichia coli (STEC). In this study, the prevalence, serotypes and virulence profiles of STEC were investigated among 130 healthy sheep from small and medium farms in southern Brazil. STEC was isolated from 65 (50%) of the tested animals and detected in all flocks. A total of 70 STEC isolates were characterized, and belonged to 23 different O:H serotypes, many of which associated with human disease, including hemolytic-uremic syndrome (HUS). Among the serotypes identified, O76:H19 and O65:H- were the most common, and O75:H14 and O169:H7 have not been previously reported in STEC strains. Most of the STEC isolates harbored only stx1, whereas the Stx2b subtype was the most common among those carrying stx2. Enterohemolysin (ehxA) and intimin (eae) genes were detected in 61 (87.1%) and four (5.7%) isolates, respectively. Genes encoding putative adhesins (saa, iha, lpfO113) and toxins (subAB and cdtV) were also observed. The majority of the isolates displayed virulence features related to pathogenesis of STEC, such as adherence to epithelial cells, high cytotoxicity and enterohemolytic activity. Ovine STEC isolates belonged mostly to phylogenetic group B1. PFGE revealed particular clones distributed in some farms, as well as variations in the degree of genetic similarity within serotypes examined. In conclusion, STEC are widely distributed in southern Brazilian sheep, and belonged mainly to serotypes that are not commonly reported in other regions, such as O76:H19 and O65:H-. A geographical variation in the distribution of STEC serotypes seems to occur in sheep.
authors.affiliation: Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina, PR, Brazil.
authors.forename: Fernando Henrique
authors.initials: FH
authors.lastname: Martins
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil. Electronic address: bec.guth@unifesp.br.
authors.forename: Beatriz Ernestina Cabilio
authors.initials: BE
authors.lastname: Guth
authors.affiliation: Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brazil.
authors.forename: Roxane Maria
authors.initials: RM
authors.lastname: Piazza
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
authors.forename: Sylvia Cardoso
authors.initials: SC
authors.lastname: Leão
authors.affiliation: Faculdade de Medicina Veterinária, Universidade Norte do Paraná, Arapongas, PR, Brazil.
authors.forename: Agostinho
authors.initials: A
authors.lastname: Ludovico
authors.affiliation: Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina, PR, Brazil.
authors.forename: Marilúcia Santos
authors.initials: MS
authors.lastname: Ludovico
authors.affiliation: Laboratorio de Referencia de E. coli (LREC), Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), Lugo, Spain.
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.affiliation: Laboratorio de Referencia de E. coli (LREC), Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), Lugo, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Marzoa
authors.affiliation: Laboratorio de Referencia de E. coli (LREC), Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), Lugo, Spain.
authors.forename: Azucena
authors.initials: A
authors.lastname: Mora
authors.affiliation: Laboratorio de Referencia de E. coli (LREC), Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), Lugo, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
authors.affiliation: Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina, PR, Brazil.
authors.forename: Jacinta Sanchez
authors.initials: JS
authors.lastname: Pelayo
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D004197:Disease Reservoirs; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D014644:Genetic Variation; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology; D006801:Humans; D060885:Multiplex Polymerase Chain Reaction / Q000662:veterinary; D010641:Phenotype; D010802:Phylogeny; D015995:Prevalence; D012703:Serotyping; D012756:Sheep / Q000382:microbiology*; D012757:Sheep Diseases / Q000453:epidemiology* / Q000382:microbiology; D022603:Shiga Toxins / Q000378:metabolism; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D022603:Shiga Toxins; D037521:Virulence Factors
keywords: Genetic diversity; Serotypes; Sheep; Shiga toxin-producing E. coli; Virulence factors