First isolation of the enterohaemorrhagic Escherichia coli O145:H- from cattle in feedlot in Argentina

PADOLA, NORA L.; SANZ, MARCELO, E; LUCCHESI, PAULA M.A.; BLANCO, JESÚS E.; BLANCO, JORGE; BLANCO, MIGUEL; ETCHEVERRÍA, ANALÍA I.; ARROYO, GUILLERMO H.; PARMA, ALBERTO E.

BMC MICROBIOLOGY

BioMedCentral

Lugar: Londres- Reino Unido; Año: 2002 vol. 2 p. 1 - 5

1471-2180

Background: Enterohaemorrhagic Escherichia coli (EHEC) is considered to be common cause ofhaemorrhagic colitis (HC), thrombotic thrombocytopenic purpura and haemolytic uraemicsyndrome (HUS) in humans. In a previous paper, we have demonstrated that EHEC are commonly found in the intestines of livestock. Infections in humans are, in part, a consequence of consumption of undercooked meat or raw milk. Argentina has one of the highest records of HUS (300–400 cases/year; 22/100,000 children under 4 years of age). The aim of this work is to communicate the first isolation of O145:H-from cattle in this country and characterize the virulence cassette, providing useful information to evaluate the risk of foodborne transmission of this emergent non- O157:H7 serotype.Results: EHEC O145:H- was isolated from cattle in an Argentinian feedlot. Pheno- and genotypeof nine strains were characterized, corresponding to several virulence cassettes: VT2+eaeA+ Mp+ (n = 5), VT2+eaeA+ (n = 1), VT1+eaeA+ Mp+ (n = 2), and VT1+eaeA+ (n = 1). Strains isolated from the same animal were considered only when they showed a different virulence pattern. The clonal relationship was studied by RAPD. Strains were distributed in two RAPD profiles, which corresponded to the presence of either, VT1+ or VT2+ genotype. No difference was detected by RAPD analysis between Mp+ or Mp- strains.Conclusions: This was the first isolation of EHEC O145:H- serotype in Argentina enlarging thelist of non-O157:H7 serotypes isolated from cattle in this country by us. All O145:H-strains carried several virulence factors which allow us to predict their potential ability to develop haemolytic uraemic syndrome in humans.