Genetic Characterization of theKlebsiella pneumoniae waaGene Cluster, Involved in Core Lipopolysaccharide Biosynthesis

Abstract

A recombinant cosmid containing genes involved in Klebsiella pneumoniae C3 core lipopolysaccharide biosynthesis was identified by its ability to confer bacteriocin 28b resistance to Escherichia coli K-12. The recombinant cosmid contains 12 genes, the whole waa gene cluster, flanked by kbl and coaD genes, as was found in E. coli K-12. PCR amplification analysis showed that this cluster is conserved in representative K. pneumoniae strains. Partial nucleotide sequence determination showed that the same genes and gene order are found in K. pneumoniae subsp. ozaenae, for which the core chemical structure is known. Complementation analysis of known waa mutants from E. coli K-12 and/or Salmonella enterica led to the identification of genes involved in biosynthesis of the inner core backbone that are shared by these three members of the Enterobacteriaceae. K. pneumoniae orf10 mutants showed a two-log-fold reduction in a mice virulence assay and a strong decrease in capsule amount. Analysis of a constructed K. pneumoniae waaE deletion mutant suggests that the WaaE protein is involved in the transfer of the branch ␤-D-Glc to the O-4 position of L-glycero-D-manno-heptose

Organism-specific platelet response and factors affecting survival in thrombocytopenic very low birth weight babies with sepsis

“…There is a variation in the genetic makeup of O antigen between Klebsiella pneumoniae and other Gram-negative organisms, which allows Klebsiella pneumoniae strains to constitutively express a polysaccharide capsule critical for the organism's ability to resist complement-mediated opsonophagocytic killing. [27][28] These genetic variations in Klebsiella pneumoniae may be responsible for the persistent bacteremia and maximum effects on various platelet parameters, as seen in our study.…”

Application of a novel multi-screening signature-tagged mutagenesis assay for identification of Klebsiella pneumoniae genes essential in colonization and infection

“…In two of the mutants, the insertions were located in genes inside the waa gene cluster, which encodes the genes involved in core LPS biosynthesis. The waaL gene encodes an O-antigen polymer ligase that is responsible for ligation of the O-antigen to the core region, while waaE presumably encodes a transferase responsible for the addition of a K. pneumoniae-specific disaccharide to the core structure (Regue et al, 2001). In the third LPS-related mutant, the insertion was inside the wbbO gene, which encodes an enzyme essential in the biosynthesis of the K. pneumoniae O-antigen (Clarke et al, 1995).…”

The Incorporation of Glucosamine into Enterobacterial Core Lipopolysaccharide

“…The genes involved in the K. pneumoniae core LPS biosynthesis are clustered in a region (wa) of the K. pneumoniae chromosome, and two different clusters have been identified to be responsible for type 1 and type 2 core biosynthesis (7,8) (Fig. 1).…”

“…1). Furthermore the functions in both inner and outer core biosynthesis of most of the transferases encoded by the wa gene products have been elucidated (7)(8)(9)(10)(11)(12) (Fig. 1).…”