HUMAN UROPATHOGENIC AND BOVINE SEPTICEMIC ESCHERICHIA-COLI STRAINS CARRY AN IDENTICAL F-17-RELATED ADHESIN

Pathogenic Escherichia coli produce fimbriae which mediate binding to mucosal cells. Generally, different fimbriae are associated with diffe rent tissular tropisms and different host specificities. Genes encodin g for pilin and adhesin subunits of two F17-related fimbriae were clon ed and sequenced. The first, G fimbriae, are synthesized by a human ur opathogenic E. coli strain, and the second, 20K fimbriae, by a bovine septicaemic E. coli strain. We showed that both fimbriae are identical and present a high homology with F17a and F17b fimbriae synthesized b y bovine enterotoxigenic E. coli strains. Furthermore, data showed tha t the G adhesin did not mediate adhesion to human uroepithelial cells, suggesting that it is not responsible for the urinary tropism of the strain and confirming the intestinal tropism specificity of F17-relate d adhesins.