Identification of enteropathogenic and enterohaemorrhagic Escherichia coli strains by immunoserological detection of intimin

ABSTRACT

To evaluate the sensitivity and specificity of polyclonal and monoclonalantibodies (Mabs) against intimin in the detection of enteropathogenic andenterohaemorrhagic Escherichia coli isolates using immunoblotting.Polyclonal and Mabs against the intimin-conservedregion were raised, and their reactivities were compared in enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC) isolates using immunoblotting analysis. In comparison with rat antiserum, rabbit anti-intimin IgG-enriched fraction had a stronger recognition pattern to a wide spectrum of intimin types in different EPEC and EHEC serotypes. On the other hand, murine monoclonal IgG2b specific to intimin, with dissociation constant of1Æ3 · 10)8 mol l)1, failed in the detection of some of these isolates. All employed antibodies showed 100% specificity, not reacting with any of the eae-negative isolates. The sensitivity range was according to the employed antisera, and 97% for rabbit anti-intimin IgG-enriched fraction, followed by 92% and 78% sensitivity with rat antisera and Mab. Significance and Impact of the Study The rabbit anti-intimin IgG-enriched fraction in immunoblotting analysis is a useful tool for EPEC and EHEC diagnoses.