The Genetic and Molecular Basis of O-Antigenic Diversity in Burkholderia pseudomallei Lipopolysaccharide

Abstract

Lipopolysaccharide (LPS) is one of the most important virulence and antigenic components of Burkholderia pseudomallei, the causative agent of melioidosis. LPS diversity in B. pseudomallei has been described as typical, atypical or rough, based upon banding patterns on SDS-PAGE. Here, we studied the genetic and molecular basis of these phenotypic differences. Bioinformatics was used to determine the diversity of genes known or predicted to be involved in biosynthesis of the O-antigenic moiety of LPS in B. pseudomallei and its near-relative species. Multiplex-PCR assays were developed to target diversity of the O-antigen biosynthesis gene patterns or LPS genotypes in B. pseudomallei populations. We found that the typical LPS genotype (LPS genotype A) was highly prevalent in strains from Thailand and other countries in Southeast Asia, whereas the atypical LPS genotype (LPS genotype B) was most often detected in Australian strains (∼13.8%). In addition, we report a novel LPS ladder pattern, a derivative of the atypical LPS phenotype, associated with an uncommon O-antigen biosynthesis gene cluster that is found in only a small B. pseudomallei sub-population. This new LPS group was designated as genotype B2. We also report natural mutations in the O-antigen biosynthesis genes that potentially cause the rough LPS phenotype. We postulate that the diversity of LPS may correlate with differential immunopathogenicity and virulence among B. pseudomallei strains.

Secondary metabolites from Bacillus amyloliquefaciens isolated from soil can kill Burkholderia pseudomallei

“…The difference in lipopolysaccharide (LPS) structure between the B. pseudomallei and B. thailandensis have been reported (Knirel et al 1992; Perry et al 1995) together with the difference in their genomes (Brett et al 1998) may contribute to the difference in their susceptibility to the antimicrobial compounds. Most of B. pseudomallei in Thailand have the LPS genotype A (Tuanyok et al 2012) and K96243 and 1026b strains with genotype A were susceptible to N2-4 and N3-8 metabolites, however, the SRM117 LPS O-side chain mutant was susceptible to N3-8 but not N2-4. Moreover, M6 and M10, which are biofilm mutants, were more susceptible to N3-8 than N2-4.…”

A Burkholderia pseudomallei Outer Membrane Vesicle Vaccine Provides Protection against Lethal Sepsis

“…However, B. pseudomallei strains K96243 and 1026b both possess LPS genotype A, the most frequent genotype (97%) found among Australian and Southeast Asian strains (29). In addition, the O-antigen biosynthesis genes are considered identical or very similar (30). This suggests that protective antibody responses induced by OMV LPS derived from strain 1026b may provide cross-protection to strain K96243 and other strains with genotype A.…”

Alteration of the Phenotypic and Pathogenic Patterns of Burkholderia pseudomallei that Persist in a Soil Environment

“…[10][11][12]35,[38][39][40] Even strains that originate from the same parental strain exhibit phenotypic diversity, particularly in colony morphology. 17,41 Both arginine deiminase and quorum sensing systems have been suggested to modulate the formation of colonies in response to different environmental conditions.…”