Both clades of the epidemic KPC-producing Klebsiella pneumoniae clone ST258 share a modified galactan O-antigen type

• Published in: International journal of medical microbiology Vol. 306; no. 2; pp. 89 - 98
• Main Authors: Szijártó, Valéria, Guachalla, Luis Miguel, Hartl, Katharina, Varga, Cecília, Banerjee, Pallavi, Stojkovic, Katarina, Kaszowska, Marta, Nagy, Eszter, Lukasiewicz, Jolanta, Nagy, Gábor
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 01.02.2016
• Subjects: Animals; Antibodies, Monoclonal - immunology; Antigens, Surface - immunology; Cloning, Molecular; d-Galactan-I; d-Galactan-III; Epitopes - immunology; Female; Galactans - classification; Galactans - genetics; Galactans - immunology; Galactans - metabolism; Hybridomas; Infectious Disease; Klebsiella pneumoniae; Klebsiella pneumoniae - classification; Klebsiella pneumoniae - genetics; Klebsiella pneumoniae - immunology; Klebsiella pneumoniae - pathogenicity; Klebsiella pneumoniae ST258; Lipopolysaccharides - immunology; LPS O-antigen; Magnetic Resonance Spectroscopy; Medical Education; Mice; Mice, Inbred BALB C; Monoclonal antibody; O Antigens - analysis; O Antigens - genetics; O Antigens - immunology; Operon - genetics; Serotype O2; Virulence; d-Galactan-III; LPS O-antigen; Monoclonal antibody; Serotype O2; d-Galactan-I; Klebsiella pneumoniae ST258
• ISSN: 1438-4221; 1618-0607
• DOI: 10.1016/j.ijmm.2015.12.002

Klebsiella pneumoniae ST258 is a globally disseminated, extremely drug resistant, nosocomial clone with limited treatment options. We show that the vast majority of ST258 isolates express modified d-galactan-I lipopolysaccharide O-antigen, termed hereinafter as d-galactan-III. The genetic determinant required for galactan-III synthesis was identified as a distinct operon adjacent to the rfb (wb) locus encoding d-galactan-I synthesis. The three genes within the operon encode predicted glycosyltransferases. Testing an isogenic transformant pair revealed that expression of d-galactan-III, in comparison to d-galactan-I, conferred improved survival in the presence of human serum. Eighty-three percent of the more than 200 ST258 draft genome sequences currently available carries the corresponding operon and hence these isolates are predicted to express galactan-III antigens. A d-galactan-III specific monoclonal antibody (mAb) was shown to bind to extracted LPS from a panel of ST258 isolates. The same mAb confirmed accessibility of galactan-III in surface staining of ST258 irrespective of the distinct capsular antigens expressed by both clades described previously. Based on these data, the galactan-III antigen may represent an attractive target for active and passive immunization approaches against K. pneumoniae ST258.