Typing of the eae and espB genes of attaching and effacing Escherichia coli isolates from ruminants

Abstract

The types of the eae and espB genes of 178 attaching and effacing Escherichia coli (AEEC) strains isolated from diarrhoeic and healthy ruminants were investigated by PCR. Six types of the eae gene: β (beta), γ1 (gamma-1), γ2 (gamma-2), ε (epsilon), ζ (zeta) and ι (iota), and three types of the espB gene: α, β and γ were identified in the strains studied. Moreover, three strains were negative to all the types of the eae gene tested. The types β and γ2 in healthy cattle, β, γ2 and ε in healthy sheep and goats, and β in diarrhoeic calves, lambs and goat kids were the most frequent types of the eae gene among the strains studied. Although the eaeβ gene was the most prevalent among AEEC from healthy and diarrhoeic ruminants, the percentages of AEEC strains with this type found in this study in diarrhoeic animals (66.7–100%) were higher than those found in healthy animals (33.3–40.6%). Thus, these data suggest that AEEC strains with the eaeβ gene are associated with neonatal diarrhoea in ruminants. The eaeγ1, eaeζ and eaeι genes were found in low percentages in the strains studied (4.5, 2.8 and 7.3%, respectively). All the types of the eae gene, except the type ι, showed a close correlation with the types of the espB gene: the eaeβ and eaeε genes with the espBβ gene, the eaeγ2 and eaeζ genes with the espBα gene and the eaeγ1 gene with the espBγ gene.