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Verotoxin-producing Escherichia coli (VTEC) and eae-positive non-VTEC in 1–30-days-old diarrhoeic dairy calves

1998; Elsevier BV; Volume: 63; Issue: 2-4 Linguagem: Inglês

10.1016/s0378-1135(98)00218-1

1873-2542

José A. Orden, José A. Ruiz-Santa-Quiteria, María Dolores Cid Vázquez, Santiago J. García, R. Sanz, Ricardo de la Fuente,

Enterobacteriaceae and Cronobacter Research

Faecal samples from 221, 1–30-days-old, diarrhoeic dairy calves were screened for the presence of verotoxin-producing Escherichia coli (VTEC) and eae-positive non-VTEC. Calves were grouped according to their age (1–7, 8–14, 15–21 and 22–30 days) and analyses of prevalences were done by Mantel–Haenzsel χ2-test for trend. VTEC and eae-positive non-VTEC were detected in 20 (9.0%) and 18 (8.1%) of the diarrhoeic calves, respectively. A significant age-associated increase in the prevalence of VTEC (p=0.0001), but not in the prevalence of eae-positive non-VTEC (p=0.381), was found. Significant differences in VTEC prevalence were found between the age-group 22–30 days and in all other age-groups. 43 (5.0%) of the 861 E. coli isolates from the 221 diarrhoeic calves were VTEC, and 30 (69.8%) of these strains produced VT1 only. More than one-half of the VTEC strains (55.8%) were positive for the eae gene and all these eae-positive VTEC strains produced VT1 only. A high percentage (76.7%) of VTEC strains belonged to E. coli serogroups (O4, O26, O39, O91, O113, O128 and O145) associated with haemorrhagic colitis and haemolytic uraemic syndrome in humans. 51 (5.9%) of the E. coli strains studied were eae-positive non-VTEC and the serogroups most prevalent among these strains were O4, O14, O26 and O123. Only four of the eae-positive strains were also espB-positive by hybridization with a probe from a human EPEC isolate and none of these strains produced VT.