Epitopes of the P-fimbrial adhesin of E. coli cause different urinary tract infections.

PURPOSE

This is a study of the interaction of the tip protein of P-fimbriae E. coli, its specific urothelial adhesin, and urothelial receptors for the adhesin. This tip protein has several epitopes that adhere to different isoreceptors containing the urothelial alpha-gal-1-4 beta-gal disaccharide. Renal tubular cells of our monkey model contain the globoside isoreceptor, and thus ureteral inoculation of E. coli with the class II tip protein leads to pyelonephritis. The class III tip protein adheres to the Forssman antigen and causes cystitis in humans.

MATERIALS AND METHODS

An E. coli strain, DS17 which originally caused pyelonephritis in a child, is P-fimbriated and contains a class II tip adhesin. A mutant was produced to contain a class III tip adhesin. Eight monkeys had a ureteral inoculation of E. coli DS17 and 4 monkeys with E. coli DS17-1. In addition, we studied in vitro adherence by these strains.

RESULTS

We show that in vitro adherence by the tip protein of P-fimbriae to bladder cells of the monkey occurs by several mechanisms, adhering to specific receptors for the class II and III epitopes of the tip protein as well as by means of type 1 fimbriae. In addition, the PapE protein of the fibrillum of the P-fimbriae adheres to fibronectin. As always, electrostatic and hydrophobic interaction remain important contributions to adherence. E. coli DS17 caused pyelonephritis, but DS17-1 caused cystitis. Bacteriuria was prolonged by DS17 infection.

CONCLUSION

The site of a urinary tract infection from P-fimbriated E. coli can be predicted by the epitope of the tip protein of P-fimbriae.