title: Virulence genes and intimin types of Shiga-toxin-producing Escherichia coli isolated from cattle and beef products in Argentina.
abstract: A total of 153 Shiga-toxin-producing Escherichia coli (STEC) isolates from feces of cattle and beef products (hamburgers and ground beef) in Argentina were characterized in this study. PCR showed that 22 (14%) isolates carried stx1 genes, 113 (74%) possessed stx2 genes and 18 (12%) both stx1 and stx2. Intimin (eae), enterohemolysin (ehxA), and STEC autoagglutinating adhesin (saa) virulence genes were detected in 36 (24%), 70 (46%) and in 34 (22%) of the isolates, respectively. None of 34 saa-positive isolates carried the gene eae, and 31 were ehxA-positive. Fourteen (7 of serotype O26:H11 and 4 of serotype O5:H-) isolates had intimin b1, 16 isolates possessed intimin g1 (11 of serotype O145:H- and 5 of serotype O157:H7), 5 isolates had intimin type e1 (4 of serotypes O103:H- and O103:H2), and one isolate O111:H- showed intimin type q/g2. Although the 153 STEC isolates belonged to 63 different seropathotypes, only 12 accounted for 58% of isolates. Seropathotype ONT:H- stx2 (18 isolates) was the most common, followed by O171:H2 stx2 (12 isolates), etc. The majority (84%) of STEC isolates belonged to serotypes previously found in human STEC and 56% to serotypes associated with STEC isolated from patients with hemolytic uremic syndrome (HUS). Thus, this study confirms that cattle are a major reservoir of STEC pathogenic for humans. To our knowledge, this is the first study that described the presence of saa gene in STEC of serotypes O20:H19, O39:H49, O74:H28, O79:H19, O116:H21, O120:H19, O141:H7, O141:H8, O174:H21, and ONT:H21. The serotypes O120:H19 and O185:H7 were not previously reported in bovine STEC.
authors.affiliation: E. coli Reference Laboratory (LREC), Department of Microbiology and Parasitology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Blanco
authors.forename: Nora L
authors.initials: NL
authors.lastname: Padola
authors.forename: Alejandra
authors.initials: A
authors.lastname: Krüger
authors.forename: Marcelo E
authors.initials: ME
authors.lastname: Sanz
authors.forename: Jesús E
authors.initials: JE
authors.lastname: Blanco
authors.forename: Enrique A
authors.initials: EA
authors.lastname: González
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.forename: Azucena
authors.initials: A
authors.lastname: Mora
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Bernárdez
authors.forename: Analía I
authors.initials: AI
authors.lastname: Etcheverría
authors.forename: Guillermo H
authors.initials: GH
authors.lastname: Arroyo
authors.forename: Paula M A
authors.initials: PM
authors.lastname: Lucchesi
authors.forename: Alberto E
authors.initials: AE
authors.lastname: Parma
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
mesh_terms: D018829:Adhesins, Bacterial / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001118:Argentina; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008461:Meat Products / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D012703:Serotyping; D022622:Shiga Toxin 1 / Q000235:genetics / Q000378:metabolism*; D022641:Shiga Toxin 2 / Q000235:genetics / Q000378:metabolism*; D014774:Virulence / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D029968:Escherichia coli Proteins; C439650:SAA protein, E coli; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2; C073819:eaeA protein, E coli