Isolation and characterisation of Shiga toxin-producing Escherichia coli O157:H7 from calves in Argentina.

Four hundred and twenty-two calves were examined for intestinal carriage of Shiga toxin-producing Escherichia coli O157:H7 using conventional plating. Two (0.5%) E. coli O157 were recovered. They were compared with 96 Argentine strains of different origin by pulsed-field gel electrophoresis, phage typing and PCR-RFLP of stx2 genes. One strain isolated from a calf, was closely related with 18 strains of clinical origin.

[Hemolytic uremic syndrome in children of Mendoza, Argentina: association with Shiga toxin-producing Escherichia coli infection]. / Síndrome urémico hemolítico en niños de Mendoza, Argentina. Asociación con la infección por Escherichia coli productor de toxina Shiga.

Shiga toxin-producing Escherichia coli (STEC) has been associated with pathogenesis of hemolytic uremic syndrome (HUS) worldwide. The aim of the present study was to characterize the HUS cases reported in Mendoza and to determine their association with STEC infection. From July 1994 through June 1996 thirty-six patients with HUS were admitted to Hospital Pediátrico "Dr. HJ Notti" (Mean age 22.8 +/- 14.9 months, 44% females). The children developed HUS following an acute diarrheal illness in 94.4% of the cases. Bloody diarrhea was observed in 83.3% of them. Antimicrobial therapy had been administered to 69.4% of the patients. Most of the patients were well-nourished (88.9%), belong to middle-low socioeconomical condition (91.7%), from urban areas (72.2%) and they were mostly assisted during summer and the beginning of autumn. The acute stage of the disease occurred with presentation of pallor (100%), edema (25%), anuria (38.9%), oliguria (41.7%), hemolytic anemia (97.2%), thrombocytopenia (86.1%) and neurological involvement (41.7%). Twenty-five of them presented the full clinical syndrome. Peritoneal dialysis were performed in 50% and packed blood cell transfusion in 88.9%. The mean days of hospitalization was 15.1 +/- 9.2 [range 1-32]. A 91.7% of the patients recovered renal function, two developed chronic renal failure and one died. Cumulative evidence of STEC infection was found in 19 (86.4%) of 22 HUS patients. STEC O157:H7, biotype C was found in 8 (36.4%). The prevalent Stx type was Stx2 in STEC, free fecal Stx (STMF) and Stx-neutralizing antibodies (a-Stx). In Mendoza, as in the rest of Argentina E. coli O157:H7, biotype C, Stx2 producer is the most frequently detected pathogen in HUS cases.