Blood group M specific haemagglutinin in pyelonephritogenic Escherichia coli

Host protein binding and adhesive properties of H6 and H7 flagella of attaching and effacing Escherichia coli

It had been suggested that the flagella of enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) might contribute to host colonization. In this study, we set out to investigate the adhesive properties of H7 and H6 flagella. We studied the abilities of EHEC EDL933 (O157:H7) and EPEC E2348/69 (O127:H6) flagella to bind to bovine mucus, host proteins such as mucins, and extracellular matrix proteins. Through several approaches, we found that H6 and H7 flagella and their flagellin monomers bind to mucins I and II and to freshly isolated bovine mucus. A genetic approach showed that EHEC and EPEC fliC deletion mutants were significantly less adherent to bovine intestinal tissue than the parental wild-type strains. In addition, we found that EPEC bacteria and H6 flagella, but not EHEC, bound largely, in a dose-dependent manner, to collagen and to a lesser extent to laminin and fibronectin. We also report that EHEC O157:H7 strains agglutinate rabbit red blood cells via their flagella, a heretofore unknown phenotype in this pathogroup. Collectively, our data demonstrate that the H6 and H7 flagella possess adhesive properties, particularly the ability to bind mucins, that may contribute to colonization of mucosal surfaces.

The host response to urinary tract infection

The authors use the UTI model to identify basic mechanisms of disease pathogenesis, host response induction, and defense. Their studies hold the promise to provide a molecular and genetic explanation for susceptibility to UTI, and to offer more precise tools for diagnosis and therapy of these infections. There are few infections where the host response is understood in such detail and where pathologic host responses can be linked to distinct disease states. The susceptibility to UTI varies greatly in the population. The studies suggest that distinct molecular defects can cause the clinical entity of acute pyelonephritis with renal scarring, and suggest that the susceptibility to UTI in certain patient groups may have a genetic basis. In addition, the distinct signal transduction pathways explain the development of symptoms, and propose that defects in those signaling mechanisms may occur in patients with ABU. In the future, it may be useful to include these host response parameters in the diagnostic arsenal, to help in early detection of patients susceptible to recurrent UTI and renal scarring. These patients may then be offered therapies that strengthen their defense, and be offered close surveillance for recurrences and other complications.

Natural selection on the erythrocyte surface

Surface glycoproteins are principal receptors used by pathogens to invade target cells. It has been suggested that mammalian erythrocyte surface glycoproteins function as decoy receptors attracting pathogens to the anucleated erythrocyte and away from their target tissues. Glycophorin A (GYPA) is solely expressed on the erythrocyte surface where it is the most abundant sialoglycoprotein, although its function is unknown. The pathogen decoy hypothesis may be relevant here, as GYPA has been shown in vitro to bind numerous viruses and bacteria, which do not infect erythrocytes. However, it is also a receptor for erythrocyte invasion by the malarial parasite Plasmodium falciparum. Analyses of gypa sequence variation among six higher primates and within a human population show that there is a large excess of replacement (nonsynonymous) substitutions along each primate lineage (particularly on exons 2-4 encoding the extracellular glycosylated domain of GYPA) and a significant excess of polymorphisms in exon 2 (encoding the terminal portion of the extracellular domain) within humans. These two signatures suggest that there has been exceptionally strong positive selection on this receptor driving GYPA divergence during primate evolution and balancing selection maintaining allelic variation within human populations. The pathogen decoy hypothesis alone is adequate to explain both these signatures of between-species and within-species diversifying selection. This has implications for understanding the functions of erythrocyte surface components and their roles in health and disease.

Probiotic agents to protect the urogenital tract against infection

The urogenital microflora of a healthy woman comprises approximately 50 species of organisms, which differ in composition according to reproductive stages and exposure to several factors, including antibiotics and spermicides. Infections are very common with > 300 million cases of urinary tract infections, bacterial vaginosis, and yeast vaginitis worldwide per annum. At the time of infection in the bladder and vagina, the urogenital flora is often dominated by the infecting pathogens, in contrast with healthy phases when indigenous organisms dominate. Premenopausal women have a flora of mostly lactobacilli, and certain properties of these strains, including adhesive ability and production of acids, bacteriocins, hydrogen peroxide, and biosurfactants, appear important in conferring protection to the host. Efforts to artificially restore an unbalanced flora with the use of probiotics have met with mixed results but research aimed at selecting scientifically based strains could well provide a reliable alternative treatment and preventive regimen to antibiotics in the future.

Identification and characterization of S fimbria-binding sialoglycoproteins on brain microvascular endothelial cells

We have previously shown that S-fimbriated Escherichia coli binds brain microvascular endothelial cells (BMEC) via a lectin-like activity of SfaS adhesin specific for NeuAc alpha2,3-galactose; however, BMEC molecules bearing these epitopes have not been identified. In the present study, we showed that the expression of S fimbriae conferred a three-fold increase in adhesion of E. coli to cow, human, and rat BMEC but did not enhance E. coli adhesion to systemic vascular endothelial cells such as human umbilical vein endothelial cells and human aortic arterial endothelial cells. Two BMEC-binding molecules for S fimbriae were identified as 65 (major)- and 130 (minor)-kDa sialoglycoproteins by S fimbria immunoblotting and were purified from bovine BMEC by wheat germ agglutinin and Maackia amurensis lectin (specific to NeuAc alpha2,3-galactose) affinity chromatography. The 65-kDa BMEC glycoprotein showed effective inhibition of S fimbria-mediated binding of E. coli to BMEC. Polyclonal antibodies raised against the mixture of 65- and 130-kDa proteins reacted to 65-kDa protein present only on BMEC, not on systemic vascular endothelial cells. Immunoprecipitation of biotinylated BMEC membrane proteins and immunocytochemistry studies of BMEC with anti-S fimbria-binding protein antibodies revealed that the 65-kDa protein is a surface protein. The N-terminal amino acid sequence of 65- and 130-kDa proteins showed no significant sequence homology with any other known proteins. These findings suggest that 65- and 130-kDa proteins represent novel sialoglycoproteins involved in the binding of S-fimbriated E. coli to BMEC.

Uropathogenic Escherichia coli adhere to urinary catheters without using fimbriae

Five well-characterized urinary and fecal isolates of Escherichia coli were found to be hydrophilic irrespective of their serotypes and their ability to express fimbriae. All the strains were able to adhere to silicone latex urinary catheters, although strain 917, which expressed type P fimbriae as its only adhesin, adhered poorly. Although specific adhesins, particularly fimbriae, have been shown to mediate adhesion of E. coli to uroepithelial cells, they do not mediate specific adhesion onto urinary catheter material. The overall surfaces of the strains, tested using microelectrophoresis as a function of pH and X-ray photoelectron spectroscopy, were not significantly different, thus suggesting more non-specific adhesion mechanisms to urinary catheters.

Blood group antigens as tumor markers, parasitic/bacterial/viral receptors, and their association with immunologically important proteins

Blood group antigens (BGAs) are chemical moieties on the red blood cell (RBC) membrane. Some BGAs (e.g., A, B, H, Lewis, P, I) are widely distributed throughout the body and may not be primarily erythroid antigens. Statistical correlations with ABO blood groups and disease have been made for years and have been highly controversial. It is not known if BGAs have a biological function. There are increasing reports of BGAs [e.g., Le(x) (an isomer of Le(a)), Le(y) (an isomer of Le(b)), T, Tn, "A-like"] appearing as "new" antigens on malignant tissue. Their presence and membrane density appears to correlate with the metastatic potential of the tumor. This often parallels loss of normal BGAs (e.g., ABH) from the tissue. Some of these antigens have been shown to influence the humoral and cellular response and have been used in assays to determine preclinical cancer, and in tumor immunotherapy. Interactions of some parasites and bacteria with human cells have been shown to depend on the presence of certain BGAs. P. vivax malarial parasites only enter human RBCs when the Fy6 Duffy blood group protein is present on the RBCs. Certain E. coli will only attach to the epithelial cells of the urinary tract if P or Dr BGAs are present in the epithelial cells. The P antigen is also the RBC receptor for Parvovirus B19. Leb has recently been found to be the receptor for H. pylori in the gastric tissue. The high frequency BGA, AnWj, is the RBC receptor for H. influenzae. BGAs have been shown to be associated closely with some important complement proteins. Ch/Rg BGAs have been found not to be true BGAs but are RBC-bound C4 (C4d). Knops/McCoy/York BGAs have been located on the C3b/C4b receptor (CR1). The high frequency BGAs of the Cromer (Cr) system are located on decay accelerating factor (DAF or CD55). Cartwright (Yt) BGAs are located on RBC acetylcholinesterase molecules. DAF and acetylcholinesterase are on phosphatidylinositol-glycan (PIG) linked proteins. When the PIG anchor is missing from RBCs, as in paroxysmal nocturnal hemoglobinuria, the affected RBCs lack all Cr, Yt, JMH, Hy/Gy, Do and Emm BGAs. The most important ligand for P, E and L selectins is sialyl-Le(x). This interaction is the tethering stage that start the leukocytes' journey from the circulation into the tissue. It appears that malignant cells may move through tissue in a similar way and may explain the close association of Le(x) with metastasis. Thus, there are increasing data suggesting a biological role for BGAs unrelated to the RBC.

Characterization of fimbriae produced by enteropathogenic Escherichia coli

Enteropathogenic Escherichia coli (EPEC) express rope-like bundles of filaments, termed bundle-forming pili (BFP) (J. A. Girón, A. S. Y. Ho, and G. K. Schoolnik, Science 254:710-713, 1991). Expression of BFP is associated with localized adherence to HEp-2 cells and the presence of the EPEC adherence factor plasmid. In this study, we describe the identification of rod-like fimbriae and fibrillae expressed simultaneously on the bacterial surface of three prototype EPEC strains. Upon fimbrial extraction from EPEC B171 (O111:NM), three fimbrial subunits with masses of 16.5, 15.5, and 14.7 kDa were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Their N-terminal amino acid sequence showed homology with F9 and F7(2) fimbriae of uropathogenic E. coli and F1845 of diffuse-adhering E. coli, respectively. The mixture of fimbrial subunits (called FB171) exhibited mannose-resistant agglutination of human erythrocytes only, and this activity was not inhibited by alpha-D-Gal(1-4)-beta-Gal disaccharide or any other described receptor analogs for P, S, F, M, G, and Dr hemagglutinins of uropathogenic E. coli, which suggests a different receptor specificity. Hemagglutination was inhibited by extracellular matrix glycoproteins, i.e., collagen type IV, laminin, and fibronectin, and to a lesser extent by gangliosides, fetuin, and asialofetuin. Scanning electron microscopic studies performed on clusters of bacteria adhering to HEp-2 cells revealed the presence of structures resembling BFP and rod-like fimbriae linking bacteria to bacteria and bacteria to the eukaryotic cell membrane. We suggest a role of these surface appendages in the interaction of EPEC with eukaryotic cells as well as in the overall pathogenesis of intestinal disease caused by EPEC.

Characteristics of Escherichia coli in acute community-acquired cystitis of adult women

The characteristics of Escherichia coli isolated from the urine in 178 consecutive episodes of community-acquired cystitis in adult women were studied and compared with strains isolated from stools of 287 healthy adults. The prevalence of each of the previously described virulence-associated factors for urinary tract infection was significantly higher in the cystitis than in the stool isolates. The figures were 25.3% and 10.8%, respectively, for P fimbriation; 19.7% and 1% for Non-P MR adhesins, 13.5% and 7.3% for type 1C fimbriae and 22.5% and 10.8% for hemolysin production. 54% of the cystitis strains (but only 21.6% of the stool isolates) had at least 1 of these virulence-associated factors. These factors were mutually associated in a non-random manner; the association of P fimbriae with K1 and of Non-P MR adhesins and type 1C fimbriae with K5 capsules were highly significant. However, no clones specifically associated with cystitis could be identified. No significant differences were found between isolates from the first or recurrent UTI, or from younger or older, compromised or non-compromised patients. We conclude that P fimbriae, Non-P MR adhesins, type 1C fimbriae and hemolysin production all contribute to the establishment of cystitis in adults.

DNA sequences of three papA genes from uropathogenic Escherichia coli strains: evidence of structural and serological conservation

Pyelonephritis-associated pili (Pap) are important in the pathogenesis of ascending, unobstructive Escherichia coli-caused renal infections because these surface bacterial organelles mediate digalactoside-specific binding to host uroepithelial cells. Pap are composed of many different polypeptides, of which only the tip proteins mediate specific binding. The PapA moiety polymerizes to form the bulk of the pilus structure and has been employed in vaccines despite its lack of Gal alpha(1-4)Gal receptor specificity. Animal recipients of PapA pilus-based vaccines are protected against experimental pyelonephritis caused by homologous and heterologous Gal-Gal-binding uropathogenic E. coli strains. Specific PapA immunoglobulin G antibodies in urine are correlated with protection in these infection models. The nucleotide sequences of the gene encoding PapA were determined for three E. coli clones expressing F7(1), F7(2), and F9 pili and were compared with corresponding sequences for other F serotypes. Specific rabbit antisera were employed in enzyme-linked immunosorbent assays to study the cross-reactivity between Gal-Gal pili purified from recombinant strains expressing F7(1), F7(2), F9, or F13 pili and among 60 Gal-Gal-binding wild-type strains. We present data which corroborate the concept that papA genes are highly homologous and encode proteins which exhibit greater than 70% homology among pili of different serotypes. The differences primarily occur in the cysteine-cysteine loop and variable regions and constitute the basis for serological diversity of these pili. Although there are differences in primary structures among these pili, antisera raised against pili of one serotype cross-reacted frequently with many other Gal-Gal pili of different serotypes. Furthermore, antisera raised against pili of the F13 serotype cross-reacted strongly or moderately with 52 (86%) of 60 wild-type Gal-Gal-binding E. coli strains. These data suggest that there are common immunogenic domains among these proteins. These additional data further support the hypothesis that broadly cross-protective PapA pilus vaccines for the immunoprophylaxis of pyelonephritis might be developed.

Frequency and organization of papA homologous DNA sequences among uropathogenic digalactoside-binding Escherichia coli strains

The frequency of selected papA DNA sequences among 89 digalactoside-binding, uropathogenic Escherichia coli strains was evaluated with 12 different synthetic 15-base probes corresponding to papA genes from four digalactoside-binding piliated recombinant strains (HU849, 201B, and 200A). The papA probes encode amino acids which are common at the carboxy terminus of all strains, adjacent to the proximal portion of the intramolecular disulfide loop of strain 210B, or predicted to constitute the type-specific epitope for each of the four recombinant strains or other epitopes of strain HU849. The presence among the strains of DNA sequence homology to the papA probes was determined by in situ colony hybridization. Hybridization data suggest that there is a high frequency of homologous papA DNA sequences corresponding to selected regions of the papA gene from strain HU849 among the clinical strains. The following nucleotide locations which encode portions of the mature HU849 PapA are detected in a high percentage (42 to 70%) of clinical isolates: 208 to 222, 310 to 324, 478 to 492, 517 to 531, 553 to 567, and 679 to 693. These sequences encode portions of the predicted protective, immunogenic, and/or antigenic epitopes of this PapA. The data also indicate considerable heterogeneity of papA sequences among the strains, especially in the region of nucleotide bases corresponding to positions 391 to 418. These oligonucleotides encode the predicted PapA type-specific immunogenic dominant epitope. Determination of the extent of genetic variability in the papA gene among digalactoside-binding strains will require more extensive DNA sequencing of prototypic papA genes, additional hybridization studies employing other papA gene oligonucleotide probes, and assessment of the different pap operons and their copy number in each strain.

Virulence factors in Escherichia coli urinary tract infection

Uropathogenic strains of Escherichia coli are characterized by the expression of distinctive bacterial properties, products, or structures referred to as virulence factors because they help the organism overcome host defenses and colonize or invade the urinary tract. Virulence factors of recognized importance in the pathogenesis of urinary tract infection (UTI) include adhesins (P fimbriae, certain other mannose-resistant adhesins, and type 1 fimbriae), the aerobactin system, hemolysin, K capsule, and resistance to serum killing. This review summarizes the virtual explosion of information regarding the epidemiology, biochemistry, mechanisms of action, and genetic basis of these urovirulence factors that has occurred in the past decade and identifies areas in need of further study. Virulence factor expression is more common among certain genetically related groups of E. coli which constitute virulent clones within the larger E. coli population. In general, the more virulence factors a strain expresses, the more severe an infection it is able to cause. Certain virulence factors specifically favor the development of pyelonephritis, others favor cystitis, and others favor asymptomatic bacteriuria. The currently defined virulence factors clearly contribute to the virulence of wild-type strains but are usually insufficient in themselves to transform an avirulent organism into a pathogen, demonstrating that other as-yet-undefined virulence properties await discovery. Virulence factor testing is a useful epidemiological and research tool but as yet has no defined clinical role. Immunological and biochemical anti-virulence factor interventions are effective in animal models of UTI and hold promise for the prevention of UTI in humans.

Mechanism of adherence of Moraxella (Branhamella) catarrhalis

We examined the mechanisms of adherence of Moraxella catarrhalis to nasopharyngeal epithelial cells. Fimbriae were detected by electron microscopy on most of the strains studied. A role of fimbriae in adherence was supported by the reduction in adherence by treatments denaturing the fimbriae or by antifimbrial antibodies. There was, however, no significant difference in adhesive capacity or hemagglutination between fimbriated and non-fimbriated strains. Furthermore, there was no correlation between hemagglutination and adherence. The possibility that receptor epitopes were provided by cell surface glycolipids was examined by thin-layer chromatography. Glycolipids from various sources, including nasopharyngeal cells were separated by thin layer chromatography plates and overlayed with bacteria. No binding was detected. The results suggest that lectin-glycolipid interactions do not explain the attachment of M. catarrhalis to epithelial cells.

Two kinds of P-fimbrial variants of uropathogenic Escherichia coli recognizing forssman glycosphingolipid

Various types of fimbriae on pathogenic Escherichia coli strains have been classified by their antigenicities and recognition specificities for receptors. However, the antigenicity of fimbrial proteins does not always correlate with the fimbrial recognition specificity. In this communication, the exact carbohydrate structures recognized by the fimbriae of two human uropathogenic E. coli strains, KS71 (O4) and IH11024 (O6), that have P-fimbrial antigen, were examined. Strain KS71 showed mannose-resistant (MR) hemagglutination (HA) of human blood group OP1 phenotype erythrocytes, and its HA was inhibited by blood group Pk antigen, Gal(alpha,1-4)Gal(beta,1-4)Glc-ceramide and P antigen, GalNAc(beta,1-3)Gal (alpha,1-4)Gal(beta,1-4)Glc-ceramide but not by Forssman antigen, GalNAc(alpha,1-3)GalNAc(beta,1-3)Gal(alpha,1-4)Gal (beta,1-4)Glc-ceramide, as previously described in many papers. The cells also showed MR HA of sheep erythrocytes, which was potently inhibited by Forssman, and weakly by P and Pk antigens. These phenomena could not be explained by the above P adhesin specificity. This adhesin was called Forssman-like adhesin. Strain IH11024 also caused MR HA of sheep erythrocytes but not of human erythrocytes. The HA was inhibited specifically by Forssman but neither by Pk nor P antigen. This adhesin was completely different from P adhesin and Forssman-like adhesin in recognition of the carbohydrate epitope. This adhesin, until now called a pseudotype of P fimbriae, was renamed Forssman adhesin.

Adhesion of enterotoxigenic Escherichia coli to the human colon carcinoma cell line Caco-2 in culture

Enterotoxigenic Escherichia coli (ETEC) strains possessing colonization factor antigen I (CFA/I), CFA/II, CFA/III, and antigen 2230 were tested for their ability to adhere to the following cell lines: HeLa, HEp-2, HRT 18, Hutu 80, MDBK, MDCK, Vero, and Caco-2. ETEC strains adhered only to the Caco-2 cell line. Irrespective of the known adhesive factors, the ETEC strains that adhered to the brush border of human enterocytes also adhered to the Caco-2 cell line. The negative variants, which were cured of the plasmid encoding the adhesive factor, did not adhere. Adhesion of ETEC strains no longer occurred when the Caco-2 cells were pretreated with the homologous colonization factor antigen or when the bacterial cells were pretreated with homologous antibodies raised against the adhesive factors. This indicates that this adhesion is specific and that a different receptor exists for each type of adhesion factor. Electron micrographs of cross sections of the monolayer showed that the adhesion of ETEC strains to the brush border microvilli does not induce any lesion. Therefore, the Caco-2 cell line behaves in the same way as human enterocytes do.

Purification and characterization of the Dr hemagglutinins expressed by two uropathogenic Escherichia coli strains

The fibrillar Dr hemagglutinins expressed by two uropathogenic Escherichia coli isolates were mechanically sheared from whole cells and subsequently purified by using anion-exchange high-pressure liquid chromatography. The isolated hemagglutinins were proteins with apparent subunit molecular masses of 14,500 daltons by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric points of 5.4 in denaturing isoelectric focusing gels. The two proteins were serologically related to each other but distinct from P fimbriae, as assessed by bacterial agglutination and immunoblotting. The amino acid compositions of the two hemagglutinins were highly similar both to each other and to other Dr hemagglutinins. N-terminal amino acid sequencing of the major hemagglutinin subunit proteins demonstrated homology with afimbrial E. coli adhesins.

F1C fimbriae of a uropathogenic Escherichia coli strain: genetic and functional organization of the foc gene cluster and identification of minor subunits

The genetic organization of the foc gene cluster has been studied; six genes involved in the biogenesis of F1C fimbriae were identified. focA encodes the major fimbrial subunit, focC encodes a product that is indispensable for fimbria formation, focG and focH encode minor fimbrial subunits, and focI encodes a protein which shows similarities to the subunit protein FocA. Apart from the FocA major subunits, purified F1C fimbriae contain at least two minor subunits, FocG and FocH. Minor proteins of similar size were observed in purified S fimbriae. Remarkably, some mutations in the foc gene cluster result in an altered fimbrial morphology, i.e., rigid stubs or long, curly fimbriae.

Variable expression of P fimbriae in Escherichia coli urinary tract infection

Fresh urinary isolates were examined by immunofluorescence with polyclonal rabbit antibodies against type 1 and P fimbriae. This procedure showed P-fimbriate Escherichia coli in 22 of 24 samples from patients with asymptomatic bacteriuria, 24 of 26 samples from patients with cystitis, and 6 of 6 samples from patients with pyelonephritis. Type 1 fimbriae were expressed by less than 40% of isolates in all three groups. There was no relation between the presence of symptoms or the site of infection and fimbrial expression, of P or type 1, by bacteria adherent to freshly isolated uroepithelial cells.

Oral vaccination of rats with live avirulent Salmonella derivatives expressing adhesive fimbrial antigens of uropathogenic Escherichia coli

The avirulent Salmonella typhimurium F885 was transformed with a plasmid carrying the cloned S fimbriae genes of a uropathogenic Escherichia coli. The resulting transformant (F885-1) produced efficiently E. coli S fimbriae and was used for live oral vaccination of rats. For comparison rats were immunized subcutaneously with isolated S fimbriae. Both routes of vaccination resulted in a significant IgG antibody response to S fimbriae. In addition live oral vaccination induced a serum IgA response against S fimbriae. After transurethral infection of rats with a S fimbriae producing E. coli a 10-fold reduction of bacterial counts in the kidney was observed in rats orally vaccinated with F885-1 as compared to unvaccinated controls. This study suggests that the avirulent Salmonella F885 may be used as a fimbrial antigen carrier for oral vaccination against renal infections.

Involvement of the MN blood group antigen in shear-enhanced hemagglutination induced by the Escherichia coli F41 adhesin

An adhesin from Escherichia coli F41 with an apparent subunit molecular weight of 28,000 daltons was isolated by using (NH4)2SO4 precipitation at pH 10 and Sephacryl S-500 gel filtration. The hemagglutination (HA) properties of the native high-molecular-weight adhesin were studied by using a viscometric assay, which provided a quantitative index of the degree of agglutination present as a function of time at a known rate of shear. Shear was found to enhance the degree of agglutination over a 20-min period. A strong, shear-enhanced HA was observed for all donors with the MM or MN blood type studied, but those with the NN blood type showed very little HA. In the microtiter HA assay, the selectivity of the adhesin for MM over NN erythrocytes was found to be dependent on pH and temperature. At 21 degrees C and pH 7.4, there was little difference in HA between the two blood types, but NN cells were progressively more weakly agglutinated than MM cells as the pH or the temperature was increased. Glycophorin A, which bears the M or N determinant, was isolated from individuals with the MM and NN blood types and was shown to be an effective inhibitor of the reaction, with the MM type being the more effective in both microtiter and viscometric assays. Acidic monosaccharides, particularly sialic acid, were also effective inhibitors of HA, although they were less potent on a molar basis than glycophorin. The adsorption isotherm of 125I-labeled adhesin was measured, and the binding was shown to be strongly inhibited by MM glycophorin and somewhat less strongly by NN glycophorin. Collectively, these data strongly suggest that glycophorin AM is a receptor for the F41 adhesin.

Isolation and characterization of the alpha-galactosyl-1,4-beta-galactosyl-specific adhesin (P adhesin) from fimbriated Escherichia coli

The alpha-galactosyl-1,4-beta-galactosyl-specific adhesin (P adhesin) was isolated from the fimbria-adhesin complex (FAC) of recombinant Escherichia coli strains expressing the F7(1), F8, or F13 fimbrial antigens. Separation into fimbriae and adhesin was achieved by heating the FAC to 80 degrees C in the presence of Zwittergent 3-16. After removal of the fimbriae by precipitation with lithium chloride, the adhesin was purified by anion-exchange fast protein liquid chromatography in the presence of 4 M urea. The purified adhesins from the three strains had pIs of 4.8 to 5.0 and molecular weights of approximately 35,000. The fimbrillins were smaller, their molecular weights being different with different F antigens. The amino-terminal amino acid sequence of the F7(1)- and F13-derived adhesins were different, that of the F13-derived adhesin being identical to that extrapolated from the DNA sequence of the papG gene (B. Lund, G. Lindberg, B.-I. Marklund, and S. Normark, Proc. Natl. Acad. Sci. USA 84:5898-5902). An antiadhesive monoclonal antibody which reacted with the three P adhesins was prepared. The FAC and the purified adhesins but not the fimbriae from which the adhesins had been removed agglutinated erythrocytes and galactose-galactose-coated latex beads. The adhesion of erythrocytes to the surface-fixed adhesins could be specifically inhibited with alpha-galactosyl-1,4-beta-galactosyl-1,4-glucosyl. The results indicate that the P adhesin(s) of uropathogenic E. coli represents a group of related proteins with conserved receptor recognition domains. The F13-derived P adhesin is the PapG protein postulated by Normark and his colleagues (Lund et al., Proc. Natl. Acad. Sci. USA 84:5898-5902; B. Lund, F. Lindberg, and S. Normark, J. Bacteriol. 170:1887-1894).

Isolation and comparison of Escherichia coli strains from canine and human patients with urinary tract infections

We analyzed Escherichia coli strains isolated from dogs with urinary tract infections (UTIs) in an attempt to determine if any of these strains were similar to E. coli isolated from humans with UTIs. Using genotypic and phenotypic traits, we identified four canine and six human E. coli UTI isolates that all appeared to be closely related or identical. All isolates shared similar DNA sequences for pyelonephritis-associated pili (pap), alpha-hemolysin (hly), and insertion sequence 5 (IS5), on the basis of Southern blot analysis. Similar outer membrane protein, pilin, and plasmid profiles were obtained for each of the isolates, although minor heterogeneity was observed. All of these isolates expressed a neuraminidase-sensitive binding phenotype in contrast to the majority of human isolates, which are known to express an adhesin that recognizes terminal digalactoside residues. Taken together, these results suggest that similar E. coli uropathogens may be capable of infecting both dogs and humans. To determine if the intestinal tracts of dogs were a reservoir for uropathogenic E. coli, eight paired rectal and urine pap+ E. coli strains were cultured from dogs with UTIs. By using the same genotypic and phenotypic criteria described above as a basis for strain identity, seven of eight urine-rectal pairs showed intrapair identity. However, each urine-rectal pair displayed a unique overall profile and could be distinguished from the other pairs. We conclude that the uropathogen colonizing the bladders of dog can also be the predominant strain colonizing the intestinal tracts.

Detection by molecular hybridization of pap, afa, and sfa adherence systems in Escherichia coli strains associated with urinary and enteral infections

The genetic determinants responsible for the adherence of Escherichia coli to uroepithelial cells have been identified in recent years by genetic and molecular methods. Specific DNA probes for each of the three operons which have been cloned so far (pap, afa, sfa/foc operons) have been used in colony hybridization experiments to detect the presence of each of these operons in the chromosomal DNA of 443 strains of E. coli; 186 strains were from patients with urinary tract infections (pyelonephritis, 106 strains; cystitis, 59; asymptomatic bacteriuria, 21) and 257 were strains from the stools of healthy subjects (61) or from patients with various enteral infections (196). E. coli strains harbouring the pap operon were found more frequently in the urine of patients with pyelonephritis (p less than 0.001) and cystitis (p less than 0.01) than in control stools. The presence of two operons (pap + afa) or (pap + sfa/foc) was only observed in uropathogenic strains (p less than 0.02). Pap and sfa/foc operons were never found in strains causing enteral infection; however, the afa operon was found in 7.6% of the enteropathogenic E. coli.

Phenotypic and genotypic assays for the detection and identification of adhesins from pyelonephritic Escherichia coli

Four different gene clusters have been characterized so far which encode adhesins involved in the specific binding of pathogenic Escherichia coli to epithelial cells of the urinary tractus: the pap, sfa, afa and bma operons. The ability to adhere to uroepithelial cells and to interact with one or several of the specific receptors identified for each of the 4 adhesins, has been studied for 102 E. coli strains isolated from patients with pyelonephritis. These receptor-binding assays are referred to as phenotypic assays. Isolates which adhered to uroepithelial cells 68.6% produced at least 1 of the previously described adhesins. In addition, we used DNA probes to detect homologous sequences of the pap, sfa, and afa operons. Genotypic assays revealed that 87.2% of pyelonephretic E. coli contain DNA sequences related to at least 1 of the 4 operons; 78.4%, 22.5% and 11.8% of the strains harboured sequences related to pap, sfa and afa operons, respectively. The afa- and sfa-adhesion determinants were commonly found associated with the presence of the pap operon (8.8% and 18.6%, respectively). Detection of adhesins using the genotypic approach appears to be reliable (all adhesins detected using the phenotypic approach were also detected with probes). Detection by colony hybridization was significantly higher than by phenotypic assay. Discrepancies may have been due to absence of expression of the detected operons and may have resulted from improper in vitro growth conditions, phase variation, and/or heterogeneity of the genes encoding the adhesins within a family of related sequences.

A hemagglutinin of uropathogenic Escherichia coli recognizes the Dr blood group antigen

A receptor moiety and blood group substance recognized by the O75X adhesin was studied. Well-defined erythrocytes representing different blood group systems and bacterial derivatives carrying plasmid pBJN406 encoding the adhesin were used in a direct hemagglutination assay. We showed that Dr blood group antigen, a component of the IFC blood group complex, is the receptor for the O75X fimbrialike adhesin (Dr hemagglutinin) of uropathogenic Escherichia coli. The molecule recognized by the Dr hemagglutinin on Dr blood group substance is a chloramphenicol-like structure. The inhibitory effect of the active compounds indicates that a tyrosine-containing molecule could be a natural receptor for the Dr hemagglutinin. Dr blood group substance was found in tubular basement membrane and Bowman's capsule of the human kidney. Specific attachment of a Dr hemagglutinin-positive bacterial strain to the kidney substructures was inhibited by chloramphenicol.

Major O-glycosylated sialoglycoproteins of human hematopoietic cells: differentiation antigens with poorly understood functions

All human hematopoietic cells seem to contain a major, heavily O-glycosylated sialoglycoprotein. Glycophorin A is specific for the erythroid lineage of cells, and leukocytes have a major sialoglycoprotein, also called leukosialin or sialophorin. Cell differentiation results in patterns of O-glycosylation in these proteins, which reflect the stage of differentiation within a cell lineage as well as lineage specificity. The altered carbohydrate compositions may influence the interactions of the cells with external ligands. Healthy individuals lacking glycophorin A in their red cells are known, whereas a deficiency of the leukocyte sialoglycoprotein may result in immunological disease. Although little is known about the physiological functions of these proteins, they form interesting models for studies on regulation of glycosylation, biosynthesis of O-glycosylated glycoproteins, and function of cell surface receptors.

Uropathogenic Escherichia coli can express serologically identical pili of different receptor binding specificities

Uropathogenic Escherichia coli frequently express P-pilus adhesins that recognize Gal alpha (1-4)Gal-containing glycoconjugates. The P-pilus adhesin of the E. coli isolate J96 is encoded by the pap gene cluster and has been shown to agglutinate P1-erythrocytes. We now describe a novel gene cluster from J96, prs, which is responsible for the agglutination of sheep erythrocytes. The structurally related gene clusters both expressed pili exhibiting the F13 antigen. Analysis of mutants of cloned prs sequences, together with trans-complementation of pap and prs genes, identified the sheep-specific adhesin as the 37-kD PrsG protein. The prsG gene occupies the equivalent position in prs as occupied by papG, which specifies the Gal alpha (1-4)Gal-specific adhesin of pap. PrsG was shown to be structurally distinct from PapG since PapG-specific antiserum did not cross-react with PrsG. Using a solid phase glycolipid receptor binding assay, PrsG was found to specify preferential binding to the Forssman antigen, a major constituent of sheep erythrocyte membranes. The binding epitope was identified as the GaINAc alpha (1-3)GaINAc moiety. This is the first direct evidence that serologically identical pili may present antigenically distinct adhesins, each capable of binding to a specific receptor.

Isolation and characterisation of dog uropathogenic Escherichia coli strains and their fimbriae

A number of Escherichia coli strains have been isolated from dogs with urinary tract infections. These strains have been characterised with respect to their O, K, H, and fimbrial antigens, colicin production, antibiotic resistance, plasmid content and their ability to haemagglutinate erythrocytes from various species. Crossed immunoelectrophoresis of fimbrial extracts, as well as the reaction of partly purified fimbriae of a number of these strains with monoclonal antibodies revealed homology or a strong crossreaction with an F12 fimbrial subunit protein of human uropathogenic E. coli strains. Unlike human F12 fimbriae producing strains, the dog isolates did agglutinate dog erythrocytes in the presence of D-mannose but not human erythrocytes, indicating that the adhesin carried by these strains is different from the adhesin on fimbriae of human uropathogenic E. coli. Similar indications were obtained from experiments with latex beads coated with the receptor for P-fimbriae. These beads were agglutinated by Escherichia coli strains from human urinary tract infections, but not by the dog isolates described here. Preliminary adhesion experiments of human and dog Escherichia coli to human bladder epithelial and canine kidney epithelial cells also showed differences in adhesion depending on the origin of the strain tested.

Distribution and degree of heterogeneity of the afimbrial-adhesin-encoding operon (afa) among uropathogenic Escherichia coli isolates

The afimbrial adhesin (AFA-I) from a pyelonephritic Escherichia coli isolate (KS52) is a mannose-resistant, P-independent, X-binding adhesin, expressed by the afa-1 operon. It is distinct from the E. coli X-binding adhesins with M and S specificity. A total of 138 E. coli isolates belonging to various serotypes, mostly from urinary tract infections, were screened for the presence of DNA sequences related to the afa operon and for the expression of an X-adhesin able to mediate mannose-resistant hemagglutination (MRHA) and adhesion to uroepithelial cells. Fifteen strains were shown to harbor DNA sequences related to the AFA-I-encoding operon, and 13 of them expressed an X-adhesin. Using as probes different DNA segments of the AFA-I-encoding operon in Southern experiments, we demonstrated that only three of these clinical isolates contained genetic determinants closely related to those identified in the original afa prototype strain (KS52): presence of the afaA, afaB, afaC, afaD, and afaE genes associated with the expression of a 16,000-dalton hemagglutinin-adhesin which strongly cross-reacted with AFA-I-specific antibodies. The other E. coli isolates harbored DNA sequences homologous to the afaA, afaB, afaC, and afaD genes, but lacked the sequence corresponding to the adhesin-producing gene afaE; Western blots allowed the detection of polypeptides (15,000, 15,500, or 16,000 daltons) in these strains which cross-reacted with variable intensity with antibodies raised against the denatured AFA-I protein, but did not cross-react with native AFA-I-specific antibodies. Following DNA cloning experiments from chromosomal DNA of two of those strains (A22 and A30), we demonstrated that although the AFA-related operon in A22 and A30 strains lacked the AFA-I adhesin-encoding gene, they synthesized a functional X-adhesin. Thus, strains A22 and A30 encode adhesins designated AFA-II and AFA-III, which were cloned on recombinant plasmids pILL72 and pILL61, respectively. Southern hybridization experiments and Western blot analyses of the 15 AFA-related strains demonstrate the heterogeneity of the genetic sequences encoding the structural adhesin and suggest the bases for the serological diversity of the AFA adhesins.

A block of urovirulence genes encoding multiple fimbriae and hemolysin in Escherichia coli O4:K12:H-

Cosmid gene libraries were constructed from a uropathogenic isolate of Escherichia coli O4:K12:H- that secretes alpha-hemolysin and produces the F14, F12-rel, F1C, and F13 fimbrial antigens. A series of overlapping clones was generated, and individual cosmid clones were found to express various combinations of fimbriae and hemolysin, suggesting that the genes for these potential virulence factors are closely linked. By using Southern hybridization analysis and restriction endonuclease mapping, it was demonstrated that the cosmid clones carried a nested set of overlapping, cloned, genomic DNA fragments. A comparison of the phenotypic properties of individual cosmid clones and subclones allowed the order of the gene clusters encoding these factors to be deduced. The cloning also revealed the presence of a fifth fimbria that had P-adhesin specificity.

Host parasite interaction in urinary tract infection

The last decade has provided new insight into the mechanisms of host-parasite interactions in the urinary tract. Reduction of host resistance appears to reduce the requirement for bacterial virulence, whereas the resistant host becomes infected with bacteria of high virulence. In the resistant host, bacterial virulence can be defined as the sum of properties required to colonize the urinary tract and induce tissue reactions. The ability to attach to uroepithelial cells is the single property most frequently associated with pyelonephritogenic clones. Attachment to the Gal alpha 1-4Gal beta-containing receptors promotes localization of bacteria to the kidney and the induction of lipopolysaccharide-mediated inflammation. Other virulence factors, defined by increased frequency in acute pyelonephritis compared with asymptomatic bacteriuria, include haemolysin and aerobactin production. Among the factors which influence the natural resistance to urinary tract infection are urinary flow and reactivity to endotoxin. The resistance induced by natural exposure to infection or immunization may be protective in experimental models, but the importance of this is not yet defined. The localization, severity and sequelae of urinary tract infection are determined by the balance between bacterial virulence and host resistance. Although disease is a result of the interaction between bacterial virulence and host resistance, these components are discussed separately for clarity.

Serological response to the P fimbriae of uropathogenic Escherichia coli in pyelonephritis

Uropathogenic Escherichia coli strains isolated from four patients with pyelonephritis were characterized by their O:K serotype, hemolysin production, mannose-resistant hemagglutination, and the serotype of the P fimbriae. These P fimbriae were serotyped with specific monoclonal antibodies. Serum samples from the patients were analyzed for the presence of specific antibodies to the P fimbriae. In all cases antifimbrial antibodies were found, strongly suggesting that these P fimbriae are expressed in vivo. However, the antibodies in the patient sera were not able to inhibit the mannose-resistant hemagglutination. This finding suggests that these antibodies react with the fimbrial components and not with the minor components which are responsible for adhesion.

Isolation and characterization of the alpha-sialyl-beta-2,3-galactosyl-specific adhesin from fimbriated Escherichia coli

The alpha-sialyl-beta-2,3-galactosyl-specific adhesin (S adhesin) was isolated from cells of a recombinant Escherichia coli K-12 strain expressing the S-fimbrial adhesin complex. A crude cell extract was partially dissociated into fimbriae and an adhesin-enriched fraction by heating to 70 degrees C. From the latter, adhesin was purified to apparent homogeneity (by fast protein liquid chromatography, immunoblot, and NaDodSO4/PAGE) by differential ammonium sulfate precipitation, dissociation in 8 M guanidine hydrochloride, and high-resolution anion-exchange chromatography in 8 M urea. The purified adhesin formed an aggregate of Mr approximately 10(6) that was made up of one type of 12-kDa polypeptide (fimbrillin is 16.5 kDa). It had pI value of 4.7 (fimbriae has a pI value of 6). Adhesin and fimbrillin had different amino acid compositions. The purified adhesins agglutinated human and bovine erythrocytes with the same specificity as the whole bacteria; purified fimbriae were not adhesive. Monoclonal anti-adhesin and anti-fimbriae antibodies were obtained. Monoclonal anti-adhesin, but none of the anti-fimbriae, antibodies inhibited the agglutination of erythrocytes. The anti-adhesive antibodies were used in immuno-gold electron microscopy to localize adhesin exclusively on the fimbriae, with a possible preference to their tips.

Binding to galactose alpha 1----4galactose beta-containing receptors as potential diagnostic tool in urinary tract infection

The diagnosis of urinary tract infection is based largely on quantitative urine cultures. The usefulness of qualitative information about the virulence of the infecting bacteria remains undefined. Ability to attach to human uroepithelial cells is one characteristic of the pyelonephritogenic clones, as well as a virulence factor per se. The identification of host cell receptors for attaching bacteria has permitted the construction of agglutination tests for simple detection of bacterial binding properties. In the present study, the reactivity with Gal alpha 1----4Gal beta-latex [galactose alpha (1----4)galactose beta-latex] and globotetraosylceramide-latex was analyzed for strains from patients with acute pyelonephritis (n = 135), acute cystitis (n = 121), and asymptomatic bacteriuria (n = 119) and from the fecal flora of healthy children (n = 120) and compared with agglutination of human blood group P1 and p, as well as guinea pig, erythrocytes. The reactivity by bioassay and the receptor-specific assays were significantly correlated. The frequency of positive reactions among the pyelonephritis isolates was 78.5% with the globotetraosylceramide-latex reagent, compared with 41% for the cystitis isolates, 25% for the asymptomatic bacteriuria isolates, and 13% for the fecal isolates. The combination of bioassays and receptor-specific assays increased the resolution of adhesins. Thus, adhesins reacting with human p erythrocytes frequently were coexpressed with Gal alpha 1----4Gal beta-specific adhesins. The receptor-specific assays provide a refined reagent to resolve bacterial binding specificities, as well as a potential tool for clinical diagnosis.

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

Specific binding to the globoseries of glycolipid receptors explains the adherence of uropathogenic Escherichia coli to host cells. The minimal receptor disaccharide Gal alpha 1----4Gal beta [galactose alpha (1----4)galactose beta] 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 into latex beads in one of two ways. In one way, di- and 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. Gal alpha 1----4Gal beta was as active as the trisaccharide derivative Gal alpha 1----4Gal beta 1----3glucose or Gal alpha 1----4Gal beta 1----3glucosamine. Among the natural glycolipids tested, globotetraosylceramide was the most active. Subsequently, the sensitivity and specificity of the Gal alpha 1----4Gal beta-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.

Monoclonal antibodies raised against Pap fimbriae recognize minor component(s) involved in receptor binding

Pap fimbriae were purified from a recombinant strain and used for the production of monoclonal antibodies (MAbs). These MAbs were screened in a fimbriae ELISA with eight different P fimbriae as well as 1A and 1C fimbriae. Five MAbs were specific for Pap fimbriae whereas one MAb did react with Pap, F7(2) and F11 fimbriae. Previously, we described two F11 MAbs which also reacted with Pap, F7(2) and F11 fimbriae. In a whole bacteria ELISA it was shown that the MAbs, which recognized Pap, F7(2) and F11 fimbriae, reacted with recombinant strains which did not express Pap or F11 fimbriae, but still expressed the globoside binding properties. Not one of the five MAbs which are specific for Pap fimbriae reacted with these globoside binding recombinant strains. In a haemagglutination and adherence assay it was shown that only the MAbs which recognized the Pap, F7(2) and F11 fimbriae inhibited the adhesive properties of the globoside binding recombinant strain. Therefore it is concluded that in the present study MAbs are presented which recognize the minor components responsible for adhesion.

Identification of two new hemagglutinins of Escherichia coli, N-acetyl-D-glucosamine-specific fimbriae and a blood group M-specific agglutinin, by cloning the corresponding genes in Escherichia coli K-12

Genes encoding the Escherichia coli IH11165 hemagglutinins with specificity for terminal N-acetyl-D-glucosamine and blood group M antigen, respectively, were cloned by a cosmid cloning procedure. A 22-kilobase-pair subclone expressed both hemagglutination specificities in the nonhemagglutinating E. coli HB101 recipient strain. Derivatives obtained by insertion and deletion mutagenesis expressed either one of the two hemagglutination specificities. Both agglutinins were purified; the agglutinin recognizing terminal N-acetyl-D-glucosamine was associated with a new type of fimbria (G fimbria) with an apparent subunit molecular mass of 19.5 kilodaltons, whereas the blood group M agglutinin (M agglutinin) was nonfimbrial and had an apparent subunit mass of 21 kilodaltons.

Oligomannoside-type glycopeptides inhibiting adhesion of Escherichia coli strains mediated by type 1 pili: preparation of potent inhibitors from plant glycoproteins

Various structurally defined glycopeptides of natural origin were tested as inhibitors of guinea pig erythrocyte agglutination by enteropathogenic Escherichia coli strains expressing type 1 pili. Besides hybrid-type glycoasparagines from ovalbumin which were not active, large oligomannoside-type carbohydrate chains from legume storage glycoproteins moderately inhibited hemagglutinations, whereas the short oligomannoside-type glycoasparagine from ovalbumin Man alpha(1----6) [Man alpha(1----3)]Man alpha(1----6)[Man alpha(1----3)] Man beta(1----4)GlcNAc beta(1----4)GlcNAc beta(1----N)Asn exhibited a potent activity. These results strongly suggested that the nonsubstitution of the alpha(1----3)-linked mannosyl residue from the N-linked glycopeptide core structure is the key determinant in the minimal structural requirement specific to this fimbrial lectin. Such Man5GlcNAc2-containing glycopeptides were obtained from larger N-linked carbohydrate chains, occurring abundantly in natural sources. The ability of jack bean alpha-mannosidase to cleave the alpha(1----2)-linked mannoses more rapidly than the others allowed the controlled digestion of large oligomannoside-type glycopeptides from legume storage glycoproteins. Such shortened glycopeptides of plant origin were prepared which strongly inhibited guinea pig erythrocyte agglutinations as well as bacterial adhesion on human buccal cells, thus confirming their similarity (if not identity) with the receptor of type 1 pili on mammalian cells. The importance of this preparation of a receptorlike compound that inhibits bacterial adhesion with regard to the research on the role of type 1 pili in E. coli pathogenicity is discussed.

Characterization of Escherichia coli wild-type strains by means of agglutination with antisera raised against cloned P-, S-, and MS-fimbriae antigens, hemagglutination, serotyping and hemolysin production

E. coli strains isolated from patients with urinary tract infections (UTI) very often possess mannose-sensitive (MS) and mannose-resistant (MR) adherence factors (fimbriae). According to their receptor specificity the mannose-resistant adhesins can be divided into several types, P, S, M and X. We have cloned the determinants of three groups of UTI E. coli adhesins, MS, P and S, and prepared specific antisera against the fimbriae antigens. 189 hemagglutination (HA+)-positive strains, 96 fecal isolates and 93 strains isolated from UTI have been tested with these specific antisera and further characterized by receptor specific HA, HA patterns and further of the "common O serogroups" 01, 02, 04, 06, 07, 08, 018, 025, 075, most prevalent in UTI, and hemolysin production. 68 (73%) of the UTI strains and 50 (52%) of the fecal isolates showed P-receptor specificity; 16 (17%) of the uropathogenic bacteria and 33 (34%) of the fecal strains exhibited S, M or X-fimbriae antigens. 24% of the P-hemagglutinating (P+) strains reacted with P (F8)-specific antiserum. In contrast, more than three quarter of the S+-strains were agglutinated by S-specific antiserum. HA-pattern VI and 018 antigen were found to be associated with P-fimbriae strains, whereas HA-pattern V and VII and the O antigens 02 (M-type), 06 and 018 (S-type) occurred most frequently in P--strains. A high percentage of P-fimbriated strains showed mannose-sensitive hemagglutination and hemolysin production.

Location of adhesion sites for P-fimbriated and for 075X-positive Escherichia coli in the human kidney

High-affinity binding sites for P-fimbriated and for 075X-positive Escherichia coli were located in the human kidney. Frozen sections of normal human kidney were double-stained first with fluorochrome-labelled bacteria and then with fluorochrome-labelled nephron site-specific lectins or antibodies. The P-fimbriate recombinant E. coli strain used showed specific adherence to glomerular structures, to the lumen of proximal and sital tubules and to vascular endothelium but did not adhere to collecting ducts or to peritubular sites. Two E. coli strains having the 075X adhesin showed specific adherence to renal interstitium, to glomerular elements and to Bowman's capsule. The method described allows the detailed determination of tissue-substructure specificity of bacterial adhesion. Our results demonstrate tissue tropism in the adhesion of E. coli to human kidneys and suggest a pathogenetic role for X adhesins.

Influence of blood group on the availability of receptors for attachment of uropathogenic Escherichia coli

Escherichia coli strains with defined receptor specificity were used as probes to analyze the individual variation in host cell receptors with respect to blood groups. The adhesins were initially characterized as mannose sensitive (MS), mannose resistant (MR), or nonagglutinating (-). The receptor specificity of the strains with MR adhesins was defined by agglutination of synthetic Gal alpha 1----4Gal beta covalently linked via a spacer arm, (CH2)2S(CH2)2CO approximately H-bovine serum albumin (BSA) to BSA-latex beads as specific for the globoseries glycolipid receptors (MR:GS). Strains with MR adhesins not reacting with Gal alpha 1----4Gal beta-BSA-latex were designated MR:nonGS. The attachment and hemagglutination of the MR:GS strains was strictly dependent on Gal alpha 1----4Gal beta-containing receptors, as shown by the absence of binding to cells from individuals of blood group P lacking these structures. Previous reports showed differences in the composition of globoseries glycolipids between erythrocytes from individuals of P1 and P2. No significant difference was found, However, in the mean adhesion to P1 and P2 epithelial cells or in the agglutination titer for P1 and P2 erythrocytes. The MR:GS receptors were equally distributed on squamous and transitional epithelial cells. In contrast, the distribution of MR:nonGS receptors was skewed. Attachment occurred mostly to squamous epithelial cells. The attachment of strains with MR:nonGS adhesins was independent of the P blood group of the cell donor. The binding ability of MR:GS and MR:nonGS adhesins appeared independent and additive. The attachment was not influenced by the ABH blood group. However, increased binding to epithelial cells from nonsecretors occurred regardless of the P blood group, suggesting a shielding of receptors by products controlled by the secretor genes. These results illustrate how individual variation in cell surface components with and without receptor activity determine the interaction of a ligand with a known receptor.

Utilization of anion-exchange chromatography and monoclonal antibodies to characterize multiple pilus types on a uropathogenic Escherichia coli O6 isolate

Multiple pilus types from a uropathogenic strain of Escherichia coli O6, strain 6260, were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), high-pressure liquid chromatography, binding assays, and erythrocyte adsorption. In addition, monoclonal antibodies were raised against purified pili of E. coli 6260 and used for immunological characterization. SDS-PAGE analysis of the purified pili showed at least three different subunits with molecular weights of 15,700, 17,800, and 19,300. SDS-PAGE analysis of four protein peaks from anion-exchange chromatography of intact pili showed polypeptides with molecular weights of 19,300 (fraction 1), 15,700 (fraction 2), and 17,800 and 15,700 (both fractions 3 and 4). Erythrocyte adsorption of the whole-pilus preparation removed the 17,800-molecular-weight subunit (17.8K subunit) and reduced the 15.7K subunit. Pili from an isogenic hemagglutination-negative variant of E. coli 6260, showing only the 15.7K and 19.3K subunits by SDS-PAGE, lacked the 17.8K subunit of fractions 3 and 4 present in the parent high-pressure liquid chromatography profile. Our data suggest that two of the pilus subunits, the 15.7K and 17.8K subunits, mediate mannose-resistant agglutination of human erythrocytes. Pili in fractions 1 and 2 from the parent strain bound specifically to mannose residues, while pili in fraction 4 bound to P-coated horse erythrocytes; no receptor specificity was identified for pili in fraction 3. Immunological analysis by the immunoblot technique showed that monoclonal antibody 11-2 reacted with the 19.3K subunit, monoclonal antibodies 34-3 and 73-3 reacted with the 15.7K subunit, and monoclonal antibodies 81-1, 82-1, and 91-1 reacted with polymers of subunits retained in the stacking gel. Intact pili precipitated by any of the six monoclonal antibodies showed two polypeptides by SDS-PAGE: 15.7K and 19.3K polypeptides for monoclonal antibody 11-2, and 15.7K and 17.8K polypeptides for monoclonal antibodies 34-3, 73-3, 81-1, 82-1, and 91-1. The cross-reactivity of the monoclonal antibodies with purified pili from other E. coli strains was determined by enzyme-linked immunosorbent assay. Monoclonal antibody 11-2 showed no significant cross-reactivity with heterogeneous pili. In contrast, the other monoclonal antibodies showed equivalent or greater reactivity with P pili from heterologous strains as compared with reactivity with E. coli 6260 pili.(ABSTRACT TRUNCATED AT 400 WORDS)