Biosynthesis of Klebsiella K2 capsular polysaccharide in Escherichia coli HB101 requires the functions of rmpA and the chromosomal cps gene cluster of the virulent strain Klebsiella pneumoniae Chedid (O1:K2).

ABSTRACT Escherichia coli is a common cause of meningitis and sepsis in the newborn infant, and the large majority of isolates from these infections produce a polysialic acid (PSA) capsular polysaccharide, the K1 antigen, that protects the bacterial cell from immune attack. We determined whether a capsule-depolymerizing enzyme, by removing this protective barrier, could alter the outcome of systemic infection in an animal model. Bacteriophage-derived endosialidase E (endoE) selectively degrades the PSA capsule on the surface of E. coli K1 strains. Intraperitoneal administration of small quantities of recombinant endoE (20 μg) to 3-day-old rats, colonized with a virulent strain of K1, prevented bacteremia and death from systemic infection. The enzyme had no effect on the viability of E. coli strains but sensitized strains expressing PSA to killing by the complement system. This study demonstrates the potential therapeutic efficacy of agents that cure infections by modification of the bacterial phenotype rather than by killing or inhibition of growth of the pathogen.

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Genomic organization of the Klebsiella pneumoniae cps region responsible for serotype K2 capsular polysaccharide synthesis in the virulent strain Chedid.

Journal of Bacteriology ◽

10.1128/jb.177.7.1788-1796.1995 ◽

1995 ◽

Vol 177 (7) ◽

pp. 1788-1796 ◽

Cited By ~ 121

Author(s):

Y Arakawa ◽

R Wacharotayankun ◽

T Nagatsuka ◽

H Ito ◽

N Kato ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Capsular Polysaccharide ◽

Genomic Organization ◽

Virulent Strain ◽

Polysaccharide Synthesis ◽

Serotype K2

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The Klebsiella pneumoniae wabG Gene: Role inBiosynthesis of the Core Lipopolysaccharide andVirulence

Journal of Bacteriology ◽

10.1128/jb.185.24.7213-7221.2003 ◽

2003 ◽

Vol 185 (24) ◽

pp. 7213-7221 ◽

Cited By ~ 55

Author(s):

Luis Izquierdo ◽

Núria Coderch ◽

Nuria Piqué ◽

Emiliano Bedini ◽

Maria Michela Corsaro ◽

...

Keyword(s):

Structural Analysis ◽

Animal Models ◽

Klebsiella Pneumoniae ◽

Gene Cluster ◽

Capsular Polysaccharide ◽

Outer Core ◽

Wild Type ◽

The Core ◽

Hydrophobic Compounds ◽

Type Strains

ABSTRACT To determine the function of the wabG gene in the biosynthesis of the core lipopolysaccharide (LPS) of Klebsiella pneumoniae, we constructed wabG nonpolar mutants. Data obtained from the comparative chemical and structural analysis of LPS samples obtained from the wild type, the mutant strain, and the complemented mutant demonstrated that the wabG gene is involved in attachment toα -l-glycero-d-manno-heptopyranose II (l,d-HeppII) at the O-3 position of anα -d-galactopyranosyluronic acid (α-d-GalAp) residue. K. pneumoniae nonpolar wabG mutants were devoid of the cell-attached capsular polysaccharide but were still able to produce capsular polysaccharide. Similar results were obtained with K. pneumoniae nonpolar waaC and waaF mutants, which produce shorter LPS core molecules than do wabG mutants. Other outer core K. pneumoniae nonpolar mutants in the waa gene cluster were encapsulated. K. pneumoniae waaC, waaF, and wabG mutants were avirulent when tested in different animal models. Furthermore, these mutants were more sensitive to some hydrophobic compounds than the wild-type strains. All these characteristics were rescued by reintroduction of the waaC, waaF, and wabG genes from K. pneumoniae.

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