title: Cloning and sequencing of the Klebsiella pneumoniae O5 wb gene cluster and its role in pathogenesis.
abstract: One representative recombinant clone encoding Klebsiella pneumoniae O5-antigen lipopolysaccharide (LPS) was found upon screening for serum resistance in a cosmid-based genomic library of K. pneumoniae KT769 (O5:K57) introduced into Escherichia coli DH5alpha. A total of eight open reading frames (wb(O5) gene cluster) were necessary to produce K. pneumoniae O5-antigen LPS in E. coli K-12. The enzymatic activities proposed for the wb(O5) gene cluster are in agreement with the activities proposed for the biosynthesis of K. pneumoniae O5-antigen LPS. Using the complete DNA sequence of the K. pneumoniae wb(O5) gene cluster, we obtained (by single or double recombination) genetically well-characterized mutants devoid only of this O5-antigen LPS. Finally, using these O5(-) mutants and the corresponding wild-type strains or complemented mutants with the wb(O5) gene cluster (O5(+) strains), we found that the presence of K. pneumoniae O5-antigen LPS is essential for some pathogenic features like serum resistance, adhesion to uroepithelial cells, and colonization (experimental infections) of the urinary tract in rats.
authors.affiliation: Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, 08071 Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Merino
authors.forename: M
authors.initials: M
authors.lastname: Altarriba
authors.forename: L
authors.initials: L
authors.lastname: Izquierdo
authors.forename: M M
authors.initials: MM
authors.lastname: Nogueras
authors.forename: M
authors.initials: M
authors.lastname: Regué
authors.forename: J M
authors.initials: JM
authors.lastname: Tomás
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000276:immunology; D005260:Female; D005798:Genes, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity; D008969:Molecular Sequence Data; D005810:Multigene Family; D016296:Mutagenesis; D019081:O Antigens / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D016366:Open Reading Frames; D051381:Rats; D017208:Rats, Wistar; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D019081:O Antigens; C409028:O5-antigen lipopolysaccharide, Klebsiella