Receptor-specific agglutination tests for detection of bacteria that bind globoseries glycolipids

Abstract

Specific binding to the globoseries of glycolipid receptors explains the adherence of uropathogenic Escherichia coli to host cells. The minimal receptor disaccharide Galdl-*4GalpI [galactosea(1-*4)galactosep] is recognized by most attaching clinical isolates. However, wild-type isolates can express adhesins with several different receptor specificities. Bioassays do not permit separate analysis of each receptor specificity, since the target cells contain multiple potentially receptor-active molecules. In this study, bacterial adhesins were analyzed by using receptors immobilized onto latex beads in one of two ways. In one way, diand trisaccharides were covalently linked via a spacer arm to latex beads coupled with bovine serum albumin. In the other way, receptor-active glycolipids were coated onto the bovine serum albumin-latex beads. The latex beads were subsequently used for agglutination by using type strains with known receptor specificity. The composition was optimized regarding receptor structure and size of latex beads. Gala1l-4GalIp was as active as the trisaccharide derivative Galal-4Galll->3glucose or Galal->4GaIfl- ,-3glucosamine. Among the natural glycolipids tested, globotetraosylceramide was the most active. Subsequently, the sensitivity and specificity of the Galkl->4GalIp-latex and globotetraosylceramide-latex reagents were compared for 733 E. coli urinary isolates. Hemagglutination of human erythrocytes was used as the positive standard. No significant difference in the specificity or sensitivity of the latex reagents was found; the sensitivity ranged from 86%, when isolates agglutinating human erythrocytes of blood groups P1 and p were included, to 93%, when those isolates agglutinating erythrocytes of blood group p were excluded. These reagents provide tools for bacterial identification in patients with urinary tract infection.

Roles of the pap- and prs-encoded adhesins in Escherichia coli adherence to human uroepithelial cells

“…Hemagglutination. The ability of bacteria to agglutinate erythrocytes was tested as previously described (6,8,9). Briefly, freshly drawn, heparinized blood samples from human donors of blood groups AP1, OP1, and Ap or from sheep were washed in PBS and resuspended to 3% (vol/vol) in PBS with 2.5% a-methyl-D-mannoside.…”

“…The receptor specificities of the P fimbriae have mainly been characterized by using particles coupled to purified glycolipids or glycolipids separated on thin-layer chromatogram plates (2,6,9,18,21,28). It has been assumed that cell surface expression of these receptor-active molecules on epithelial cells is sufficient for attachment to occur.…”

Human blood groups: incidental receptors for viruses and bacteria

“…'~ Fimbriated strains that recognize P differ slightly in their binding specificity, with some showing greater adherence to globoside (P) than to ceramide trihexoside (PK>, and some recognizing globoside but not the Galal,4Gal moiety alone. 30 Only about one third of P-fimbriated strains recognize the internal Gala1,4Gal moiety of the Forsmann antigen, the predominant glycolipid antigen of sheep red cells.31 Some P antigen-recognizing strains, termed ONAP (for 0-negative, A-p~sitive),~~ adhere better to PI red cells of the A blood group than to those of 0 or B groups.33 These strains require both the Galal,4Gal moiety and the A-specific trisaccharide (GalNAc[ 1 -3]Fuc[ 1-2lGal) for hemagglutination'2 and bind with high affinity to globo-A and to the Forsmann antigen, but not to other globoseries gly~olipids. '~ Molecular cloning of different fimbrial types and studies of binding specificities have allowed investigators to isolate a family of related P adhesins.…”

P1-antigen-containing avian egg whites as inhibitors of P adhesins among wild-type Escherichia coli strains from patients with urosepsis

“…Duguid et al originally described the temperature dependence of E. coli-mediated hemagglutination (5). Some contemporary investigators have done MRHA assays at room temperature (1,4,20,34,39,44,45); others have done such assays in the cold (7,29,32,36,37,46). The influence of assay temperature on MRHA phenotype should be considered in interpreting the results of such studies.…”