DEVELOPMENT OF EXPERIMENTAL-MODEL OF CHRONIC PYELONEPHRITIS WITH ESCHERICHIA-COLI O75-K5-H-BEARING DR FIMBRIAE - MUTATION IN THE DRA REGIONPREVENTED TUBULOINTERSTITIAL NEPHRITIS

Escherichia coli that express Dr fimbriae and related adhesins recogni ze the common receptor decay accelerating factor. E. coli strains that express adhesins of the Dr family were postulated to be associated wi th cystitis (30-50%), pregnancy-associated pyelonephritis (30%), and c hronic diarrhea (50%). In this study, we investigated the hypothesis t hat E. coli renal interstitial binding mediated by the Dr adhesin may be important for the development of chronic pyelonephritis, An inserti onal dra mutant, E. coli DR14, of the clinical E. coli isolate IH11128 bearing Dr fimbriae, was constructed and used to characterize persist ence of infection and interstitial tropism in an experimental model of ascending pyelonephritis. Quantitative cultures of kidney homogenates indicated that Dr hemagglutinin positive (Dr+) E. coli IH11128 establ ished a 1-yr colonization of renal tissue. In the Dr hemagglutinin neg ative (Dr-) group, 50% of animals cleared infection within 20 wk and 1 00% between 32 to 52 wk. Dr+ E. coli colonized the renal interstitium. Significant histological changes corresponding to tubulointerstitial nephritis including interstitial inflammation, fibrosis, and tubular a trophy were found in the kidney tissue of the Dr+ but not the Dr- grou p. A substantial amount of fimbrial antigen was detected in the parenc hymal regions affected by interstitial inflammation and fibrosis. The obtained results are consistent with the hypothesis that mutation with in the dra region, affecting E. coli binding to tubular basement membr anes, prevented renal interstitial tropism and the development of the changes characteristically seen in tubulointerstitial nephritis.