First isolation of the enterohaemorrhagic Escherichia coli O145:H- from cattle in feedlot in Argentina.
BACKGROUND
Enterohaemorrhagic Escherichia coli (EHEC) is considered to be common cause of haemorrhagic colitis (HC), thrombotic thrombocytopenic purpura and haemolytic uraemic syndrome (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 genotype of 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 the list 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.
Padola
Nora L
NL
Laboratorio de Inmunoquímica y Biotecnología, Animal Health Department, Universidad Nacional del Centro-CIC, 7000 Tandil, Argentina. nlpadola@vet.unicen.edu.ar
Sanz
Marcelo E
ME
Lucchesi
Paula M A
PM
Blanco
Jesús E
JE
Blanco
Jorge
J
Blanco
Miguel
M
Etcheverría
Analía I
AI
Arroyo
Guillermo H
GH
Parma
Alberto E
AE
D000821:Animal Feed / Q000382:microbiology*; D000818:Animals; D001118:Argentina; D002417:Cattle; D019453:Escherichia coli O157 / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism / Q000472:pathogenicity; D006470:Hemorrhage / Q000382:microbiology*; D019105:Random Amplified Polymorphic DNA Technique; D012703:Serotyping; D022603:Shiga Toxins / Q000378:metabolism; D014774:Virulence
D022603:Shiga Toxins