[Prevalence of enterohemorrhagic Escherichia coli in a cattle area of Argentina. Genotypic characterization of the strains of animal origin].
BACKGROUND
There is a high prevalence of infection by Enterohemorrhagic Escherichia coli (EHEC) and patients with hemolytic uremic syndrome (HUS) in Argentina.


OBJECTIVE
To study cattle and pigs as a possible reservoir of EHEC in Argentina.


METHODS
One hundred two healthy animals (68 cattles and 31 pigs) from a livestock in Argentina, were studied. Stool samples were obtained with a rectal swab. The strains were identified by DNA hybridization with specific gene probes detecting Shiga-like toxin 1 and 2 (Stx1, Stx2), and hly gen related to fimbrial adhesin-associated plasmid. EHEC strains were serogrouped using commercial antisera.


RESULTS
EHEC was isolated from 30 out of 68 bovines cultures (44.1%) and from 25 out of 31 pigs (58.1%). Isolates carrying genes codifying both Stx1 and Sxt2, were observed in 50% of cattle and 63.9% of pigs. The gene which codifies for hemolysin (associated to fimbrial adhesin) was observed in about 41% of EHEC isolates. Strains belonging to serogroups O26, O111, and O157 were isolated from cattle, and O111, and O157 from pigs.


CONCLUSIONS
The high percentage of EHEC in both cattle and pigs and the presence of human infection-associated serogroups, suggests that these animals are a reservoir of EHEC associated with disease in humans.
Cátedra de Microbiología, Facultad de Ciencias Médicas, Cátedra de Inmunología, Facultad de Ciencias Veterinarias, Universidad Nacional de Rosario, Argentina.
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D000818:Animals; D001118:Argentina / Q000453:epidemiology; D002353:Carrier State / Q000382:microbiology / Q000662:veterinary*; D002417:Cattle; D004199:Disease Vectors; D004927:Escherichia coli Infections / Q000453:epidemiology; D019453:Escherichia coli O157 / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D011247:Pregnancy; D015995:Prevalence; D013552:Swine