The role of fimbriae of uropathogenic Escherichia coli as carriers of the adhesin involved in mannose-resistant hemagglutination (original) (raw)
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Zentralblatt für Bakteriologie, Mikrobiologie und Hygiene. Series A: Medical Microbiology, Infectious Diseases, Virology, Parasitology, 1986
E. coli stcains isolated from patients with urinary tcact infecrions (UTn very often possess mannose"sensitive (MS) and mannose-resistant (MR) adherence facmrs (fimbriae). According to their receptor specificity the mannose-resistant adhesins can be divided inm several types, P, S, M and X. We have cloned rhe determinants of rhree groups of UTI E. coli adhesins, MS, p and S, and prepared specific aorisera against the fimbriae antigens. 189 hernagglutination (HA+)-positive stcains, 96 fecal isolates and 93 strains isoJated from UTI. have been tesred with rhese specific antisera and further characterized by receptor specific : HA, HA parteras and further of rhe "common 0 serogroups"
Microbiology, 1986
~~ Deletion mutants of recombinant plasmids encoding the KS7lB fimbrial antigens of the uropathogenic Escherichia coli strain KS7 1 (04 : K12) were constructed. The effects of these mutations were tested by transforming the mutated plasmids into non-fimbriated E. coli HBlOl cells and testing the transformants for fimbriation and haemagglutination. A deletion transcriptionally upstream from the fimbrial subunit gene increased the expression of KS7 1 B fimbriae. Deletion of the fimbrial subunit gene resulted in non-fimbriated but haemagglutinating transformants, whereas a deletion 6 kb transcriptionally downstream from the subunit gene resulted in non-haemagglutinating but fimbriate transformants, indicating that fimbriation and haemagglutination were genetically separable. We also present evidence suggesting that the fimbrillin and haemagglutinin are physically associated in the wild-type KS7 1 strain.
Proceedings of the National Academy of Sciences, 2008
Signatures of Positive Selection in the FimH SP. Phylogenetic analysis of fimH sequences from E. coli isolates revealed six nonsynony-MICROBIOLOGY LSpBB, LS76, LS60, and LS141 were used. Static binding was performed as described (40). Bacterial surface accumulation over 5 min and fraction rolling were measured as described (29). For detachment experiments, bacteria at 2 ϫ 10 9 cells/ml were allowed to briefly bind statically to the flow chamber surface. Flow with PBS-BSA buffer alone was applied at 0.27 Pa to remove free-floating bacteria. Flow was applied at 2 Pa for 1 min to promote high-affinity binding and fimbrial uncoiling. Then, flow was decreased to 0.01 Pa and the percentage of bacteria that remained attached at each second relative to the average number attached over the last 30 s of the 2-Pa section was calculated.
Molecular …, 2006
Mannose-binding type 1 pili are important virulence factors for the establishment of Escherichia coli urinary tract infections (UTIs). These infections are initiated by adhesion of uropathogenic E. coli to uroplakin receptors in the uroepithelium via the FimH adhesin located at the tips of type 1 pili. Blocking of bacterial adhesion is able to prevent infection. Here, we provide for the first time binding data of the molecular events underlying type 1 fimbrial adherence, by crystallographic analyses of the FimH receptor binding domains from a uropathogenic and a K-12 strain, and affinity measurements with mannose, common monoand disaccharides, and a series of alkyl and aryl mannosides. Our results illustrate that the lectin domain of the FimH adhesin is a stable and functional entity and that an exogenous butyl a a a a -D -mannoside, bound in the crystal structures, exhibits a significantly better affinity for FimH (K d = 0.15 m m m m M) than mannose (K d = 2.3 m m m m M). Exploration of the binding affinities of a a a a -D -mannosides with longer alkyl tails revealed affinities up to 5 nM. Aryl mannosides and fructose can also bind with high affinities to the FimH lectin domain, with a 100-fold improvement and 15-fold reduction in affinity, respectively, compared with mannose. Taken together, these relative FimH affinities correlate exceptionally well with the relative concentrations of the same glycans needed for the inhibition of adherence of type 1 piliated E. coli . We foresee that our findings will spark new ideas and initiatives for the development of UTI vaccines and anti-adhesive drugs to prevent anticipated and recurrent UTIs.
Determination of Adhesion Encoding Genes of Uropathogenic Escherichia coli
Avicenna Journal of Clinical Microbiology and Infection, 2018
Background Uropathogenic Escherichia coli (UPEC), the causative agent of urinary tract infections (UTIs) in otherwise healthy individuals, is a frequently encountered pathogen (1). The UPEC belongs to a subgroup of extraintestinal pathogenic E. coli's which causes a broad spectrum of conditions including bacteraemia, UTIs, and neonatal meningitis in man and colibacillosis in poultry (2). Eighty percent of acute UTIs is associated with E. coli. The infection initiates when the bacteria adhere to the uroepithelial cell receptors through specific fimbrial adhesins (3). E. coli is part of the normal microbiota of the enteric tract of humans and animals. The mutually beneficial symbiotic association of E. coli with its host helps maintaining normal intestinal homeostasis and promoting the stability of the intestinal microbial flora (4). UTI results in substantial medical costs. UPEC is associated with community acquired UTIs and nosocomial UTIs, as well as with considerable morbidity and mortality worldwide (5). The UPEC ability to cause symptomatic UTIs is dependent on the expression of broad spectrum virulence factors (6). Molecules of adhesion and toxins account for the most important mediators of pathogenicity. UPEC receptor binding protein can be differentiated on the basis of their receptor identifying capabilities. The P-fimbriae which is encoded by the pap operon of E. coli will bind to digalactoside containing receptors (7). Sialic acid containing receptors are those for S-fimbriae which is encoded by sfa operon. Afimbrial adhesin is encoded by afa operon and is associated with recurrent UTIs (8). The virulence factors are helpful in colonization and persistence of bacteria in the urinary tract. Adhesins or Fimbriae, toxins, and siderophore systems are involved in initiation of UTI by colonization to host tissues (9). Extraintestinal infections causing E. coli expresses mannose resistant adhesins and pap fimbriae is the most common one (10). The pap (pyelonephritis associated pilus) operon mediates galactosyl galactose specific binding to epithelial surfaces of intestine, vagina, urinary tract, and moiety of the P blood group by their tip adhesion molecule (11,12). The S fimbrial adhesins are frequently expressed in E. coli strains involved in extraintestinal infections (13). The S fimbriae are also mannose resistant and associated with E. coli strains that cause sepsis, meningitis, and ascending UTIs; they help in the bacterial spread within host tissues (14). The E. coli
Molecular analysis and epidemiology of the Dr hemagglutinin of uropathogenic Escherichia coli
Infection and immunity, 1989
The genetic organization and epidemiology of Dr hemagglutinin was studied. Plasmids derived from pBJN406 and carrying transposon inserts were analyzed for their abilities to confer the mannose-resistant hemagglutination phenotype and expression of plasmid-encoded proteins. The 6.6-kilobase DNA fragment expressed five polypeptides with molecular masses of 15.5, 5, 18, 90, and 32 kilodaltons encoded by the draA, draB, draC, draD, and draE genes, respectively. Four genes, draA, draC, draD, and draE, were required for full mannose-resistant hemagglutination expression. Mutation in the draA gene, previously identified as encoding fimbrillin, resulted in loss of the adherence phenotype. We screened 658 strains isolated from patients with urinary tract infections (UTI) or from fecal samples for the presence of DNA sequences homologous to the draD gene. A significantly higher frequency of draD-related sequences was found among Escherichia coli strains from patients with cystitis than among ...