title: Reconstitution of O-specific lipopolysaccharide expression in Burkholderia cenocepacia strain J2315, which is associated with transmissible infections in patients with cystic fibrosis.
abstract: Burkholderia cenocepacia is an opportunistic bacterium that infects patients with cystic fibrosis. B. cenocepacia strains J2315, K56-2, C5424, and BC7 belong to the ET12 epidemic clone, which is transmissible among patients. We have previously shown that transposon mutants with insertions within the O antigen cluster of strain K56-2 are attenuated for survival in a rat model of lung infection. From the genomic DNA sequence of the O antigen-deficient strain J2315, we have identified an O antigen lipopolysaccharide (LPS) biosynthesis gene cluster that has an IS402 interrupting a predicted glycosyltransferase gene. A comparison with the other clonal isolates revealed that only strain K56-2, which produced O antigen and displayed serum resistance, lacked the insertion element inserted within the putative glycosyltransferase gene. We cloned the uninterrupted gene and additional flanking sequences from K56-2 and conjugated this plasmid into strains J2315, C5424, and BC7. All the exconjugants recovered the ability to form LPS O antigen. We also determined that the structure of the strain K56-2 O antigen repeat, which was absent from the LPS of strain J2315, consisted of a trisaccharide unit made of rhamnose and two N-acetylgalactosamine residues. The complexity of the gene organization of the K56-2 O antigen cluster was also investigated by reverse transcription-PCR, revealing several transcriptional units, one of which also contains genes involved in lipid A-core oligosaccharide biosynthesis.
authors.affiliation: Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada N6A 5C1.
authors.forename: Ximena
authors.initials: X
authors.lastname: Ortega
authors.forename: Tracey A
authors.initials: TA
authors.lastname: Hunt
authors.forename: Slade
authors.initials: S
authors.lastname: Loutet
authors.forename: Arlene D
authors.initials: AD
authors.lastname: Vinion-Dubiel
authors.forename: Anup
authors.initials: A
authors.lastname: Datta
authors.forename: Biswa
authors.initials: B
authors.lastname: Choudhury
authors.forename: Joanna B
authors.initials: JB
authors.lastname: Goldberg
authors.forename: Russell
authors.initials: R
authors.lastname: Carlson
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Valvano
mesh_terms: D019117:Burkholderia / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity*; D019121:Burkholderia Infections / Q000382:microbiology* / Q000635:transmission; D003165:Complement System Proteins / Q000276:immunology; D003227:Conjugation, Genetic; D003550:Cystic Fibrosis / Q000382:microbiology*; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008070:Lipopolysaccharides / Q000096:biosynthesis* / Q000737:chemistry; D008969:Molecular Sequence Data; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D019081:O Antigens / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA; D014312:Trisaccharides / Q000737:chemistry / Q000302:isolation & purification; D037521:Virulence Factors / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D008070:Lipopolysaccharides; D019081:O Antigens; D014312:Trisaccharides; D037521:Virulence Factors; D003165:Complement System Proteins; D016695:Glycosyltransferases