Detection of Escherichia coli adhesins with DNA probes

DNA hybridization assays for genes encoding the Escherichia coli adhesins K88 and K99 were developed. These assays were used to screen a variety of animal E. coli strains, and the results were compared with results obtained by serological methods. All methods compared well for determining the presence of adhesin K99. However, the DNA hybridization detected more K88-positive strains than did either enzyme immunoassay or slide agglutination. Agreement was improved when strains were grown on blood or nutrient agar instead of Minca medium.