rpsU-based discrimination within the genus Burkholderia

Sequencing of the gene rpsU reliably delineates saprophytic Burkholderia (B.) thailandensis from highly pathogenic B. mallei and B. pseudomallei. We analyzed the suitability of this technique for the delineation of the B. pseudomallei complex from other Burkholderia species. Both newly recorded and previously deposited sequences of well-characterized or reference strains (n = 84) of Azoarcus spp., B. ambifaria, B. anthina, B. caledonica, B. caribensis, B. caryophylli, B. cenocepacia, B. cepacia, B. cocovenenans, B. dolosa, B. fungorum, B. gladioli, B. glathei, B. glumae, B. graminis, B. hospita, B. kururensis, B. mallei, B. multivorans, B. phenazinium, B. phenoliruptrix, B. phymatum, B. phytofirmans, B. plantarii, B. pseudomallei, B. pyrrocinia, B. stabilis, B. thailandensis, B. ubonensis, B. vietnamiensis, B. xenovorans, not further defined Burkholderia spp., and the outliers Cupriavidus metallidurans, Laribacter hongkongensis, Pandorea norimbergensis, and Ralstonia pickettii were included in a multiple sequence analysis. Multiple sequence alignments led to the delineation of four major clusters, rpsU-I to rpsU-IV, with a sequence homology >92%. The B. pseudomallei complex formed the complex rpsU-II. Several Burkholderia species showed 100% sequence homology. This procedure is useful for the molecular confirmation or exclusion of glanders or melioidosis from primary patient material. Further discrimination within the Burkholderia genus requires other molecular approaches.