dra-Related X adhesins of gestational pyelonephritis-associated Escherichia coli recognize SCR-3 and SCR-4 domains of recombinant decay- accelerating factor

T. Pham, A. Kaul, A. Hart, P. Goluszko, J. Moulds, S. Nowicki, D. M. Lublin, B. J. Nowicki

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

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-3Δ 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-4Δ mutant but unaffected by an SCR-3Δ 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.

Original languageEnglish
Pages (from-to)1663-1668
Number of pages6
JournalInfection and Immunity
Volume63
Issue number5
DOIs
StatePublished - 1995

Fingerprint Dive into the research topics of 'dra-Related X adhesins of gestational pyelonephritis-associated Escherichia coli recognize SCR-3 and SCR-4 domains of recombinant decay- accelerating factor'. Together they form a unique fingerprint.

  • Cite this