Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034186 (pyelonephritis)
 6,144 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bacterial adhesins are important virulence factors that allow colonization of the human urogenital tract by Escherichia coli. Adhesins of the Dr family have been found to be more frequently expressed in strains associated with symptomatic urinary tract infections. Because of the high frequency of symptomatic urinary tract infections during pregnancy, we screened E. coli isolates from 64 gestational pyelonephritis patients for the expression of Dr and X adhesins to address their potential virulence roles in this population. Using PCR and primers for the afaB gene, we detected dra-related operons in 17 isolates (27%). On the basis of the lack of hemagglutination of Dr(a-) erythrocytes containing a point mutation in the decay-accelerating factor (DAF) short consensus repeat-3 (SCR-3) domain, 12 of these strains were categorized as classical Dr adhesins. The hemagglutination of O erythrocytes by Dr+ strains was blocked or reduced by a monoclonal antibody to the DAF SCR-3 domain. The remaining five dra-positive strains agglutinated Dr(a-) erythrocytes. Monoclonal antibody to the DAF SCR-3 domain failed to block O-erythrocyte hemagglutination. Adhesins in these strains did not fulfill criteria for Dr hemagglutinins because of the undefined receptor specificities and were categorized as X. E. coli strains bearing dra-related X adhesins bound to DAF cDNA-transfected Chinese hamster ovary cells. Three of these dra-related X-adhesin-bearing E. coli strains failed to attach to the SCR-3 delta deletion transfectant, which suggested that binding sites were located in the SCR-3 domain but outside the region blocked by the monoclonal anti-SCR-3 immunoglobulin G. The binding sites of the remaining two dra-related X adhesin strains were localized to the SCR-4 domain, as the attachment was shown to be abolished on an SCR-4 delta mutant but unaffected by an SCR-3 delta deletion. The heterogeneity in the binding sites of E. coli DAF (Dr) family adhesins from gestational pyelonephritis isolates may reflect the ability of the adhesins to evolve to recognize alternate peptide epitopes for efficient colonization.
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PMID:dra-related X adhesins of gestational pyelonephritis-associated Escherichia coli recognize SCR-3 and SCR-4 domains of recombinant decay-accelerating factor. 753 46

Bacterial adhesins play an important role in the colonization of the human urogenital tract. Escherichia coli Dr family adhesins have been found to be frequently expressed in strains associated with pyelonephritis in pregnant females. The tissue receptor for known Dr adhesins has been localized to the short consensus repeat-3 (SCR-3) domain of decay accelerating factor (DAF), a complement regulatory protein. In this report, we identified and cloned draE2, a gene encoding a novel 17-kDa DAF-binding adhesin, Dr-II, from a strain of E. coli associated with acute gestational pyelonephritis. Despite the significant sequence diversity between Dr-II and Dr family adhesins, the receptor of Dr-II was found to be the SCR-3 domain of DAF. Sequence analysis of the 186-amino-acid Dr-II open reading frame revealed significant diversity from other members of the Dr adhesin family, including Dr, AFA-I, AFA-III, and F1845, but only an 8-amino-acid difference in sequence from that of the 17-kDa nonfimbrial adhesin NFA-I of unknown receptor specificity. N-terminal peptide sequencing of the purified adhesin confirmed the identity of the open reading frame and indicated cleavage of a 28-amino-acid signal peptide. Antibodies raised against purified Dr-II adhesin exhibited little or no cross-reactivity to Dr adhesin. Characterization of the biological properties demonstrated that like the Dr adhesins, Dr-II was associated with the ability of E. coli to bind to tubular basement membranes and Bowman's capsule and to be internalized into HeLa cells.
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PMID:Molecular cloning and characterization of Dr-II, a nonfimbrial adhesin-I-like adhesin isolated from gestational pyelonephritis-associated Escherichia coli that binds to decay-accelerating factor. 931 41