Structural analysis of capsular polysaccharides expressed by Burkholderia mallei and Burkholderia pseudomallei

Capsular polysaccharides (CPSs) were isolated from O-polysaccharide deficient strains of Burkholderia mallei and Burkholderia pseudomallei using a modified hot phenol/water extraction procedure. Glycosyl composition, methylation, MALDI-TOF MS analyses as well as 1H NMR spectroscopy including COSY, TOCSY, NOESY, HMBC and HSQC experiments identified the presence of two distinct CPS antigens in the samples exhibiting the following structures:Figure optionsDownload as PowerPoint slideThis study confirms the ability of B. mallei to express a 6-deoxy-heptan CPS and represents the first report of a mannan CPS being expressed by these bacterial pathogens.

Figure optionsDownload as PowerPoint slideHighlights
► Burkholderia mallei and Burkholderia pseudomallei are select agent bacteria.
► B. mallei and B. pseudomallei express multiple CPS antigens.
► The 1,3-linked 6-deoxy-heptan is both a virulence factor and protective antigen.
► The 1,3-linked 6-deoxy-heptan is a promising vaccine candidate.
► The 1,3-linked α-mannan represents a newly discovered CPS antigen.