title: Virulence traits and different nle profiles in cattle and human verotoxin-producing Escherichia coli O157:H7 strains from Argentina.
abstract: Verotoxin-producing E. coli (VTEC) O157:H7 is the dominant serotype isolated from patients with HUS and, Argentina has the highest rate of HUS in the world. Molecular typing had allowed to identify subpopulations related to the origin and virulence of O157:H7 strains. Our aim was to perform a genetic characterization of 43 O157:H7 strains isolated in Argentine mostly from cattle and humans in order to establish the potential public health risk. For it, we used a combination of molecular subtyping methods in order to identify clade 8_rhsA (C3468G), LSPA-6 and virulence profiles and, a cytotoxicity assay on Vero cell. All isolates carried the clade 8 SNP variant and 98% of them belonged to lineage I/II (2% lineage II). Isolates were grouped into eleven nle profiles, 46% were positive for all nle genes, while the remaining isolates, except two, showed incomplete OI-71, particularly lacked nleF. All isolates showed the plasmid profile ehxA-espP-katP-stcE and harbored ehaA, elfA, iha and lpfA variants lpfA1-3 and lpfA2-2 and, ECSP_0242. The frequencies of the remaining ECSP genes were 95% ECSP_2687, 88% ECSP_3286, 86% ECSP_3620, 53% ECSP_2870/2872 and 44% ECSP_1733. All O157:H7 strains, except the isolate identified as lineage II, were cytotoxic on Vero cells. Among Argentinean strains, most genetic markers occur at equal relative frequencies among clinical and bovine isolates, showing diversity mostly in nle genes profiles. The belonging of the isolates to hypervirulent clade 8 and lineage I/II, the high prevalence of nle and putative virulence factors genes, would allow assigning most O157:H7 strains of this region a high risk to public health.
authors.affiliation: Laboratorio de Inmunoquímica y Biotecnología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, 7000 Tandil, Argentina.
authors.forename: Juliana
authors.initials: J
authors.lastname: González
authors.affiliation: Laboratorio de Inmunoquímica y Biotecnología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, 7000 Tandil, Argentina.
authors.forename: Andrea Mariel
authors.initials: AM
authors.lastname: Sanso
authors.affiliation: Laboratorio de Inmunoquímica y Biotecnología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, 7000 Tandil, Argentina.
authors.forename: Jimena Soledad
authors.initials: JS
authors.lastname: Cadona
authors.affiliation: Laboratorio de Inmunoquímica y Biotecnología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, 7000 Tandil, Argentina. Electronic address: avbustaman@vet.unicen.edu.ar.
authors.forename: Ana Victoria
authors.initials: AV
authors.lastname: Bustamante
mesh_terms: D000818:Animals; D001118:Argentina / Q000453:epidemiology; D001422:Bacterial Adhesion / Q000235:genetics; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology*; D016000:Cluster Analysis; D019453:Escherichia coli O157 / Q000145:classification / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics*; D005838:Genotype; D006463:Hemolytic-Uremic Syndrome / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D022603:Shiga Toxins / Q000096:biosynthesis*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D022603:Shiga Toxins; D037521:Virulence Factors
keywords: O157:H7; Subtyping; Verotoxin-producing Escherichia coli; Virulence factors