Burkholderia humptydooensis sp. nov., a New Species Related to Burkholderia thailandensis and the Fifth Member of the Burkholderia pseudomallei Complex

During routine screening for from water wells in northern Australia in areas where it is endemic, Gram-negative bacteria (strains MSMB43 , MSMB121, and MSMB122) with a similar morphology and biochemical pattern to and were coisolated with on Ashdown's selective agar. To determine the exact taxonomic position of these strains and to distinguish them from and , they were subjected to a series of phenotypic and molecular analyses. Biochemical and fatty acid methyl ester analysis was unable to distinguish sp. nov. from closely related species. With matrix-assisted laser desorption ionization-time of flight analysis, all isolates grouped together in a cluster separate from other spp. 16S rRNA and sequence analyses demonstrated phylogenetic placement for sp. nov. in a novel clade within the group. Multilocus sequence typing (MLST) analysis of the three isolates in comparison with MLST data from 3,340 strains and related taxa revealed a new sequence type (ST318). Genome-to-genome distance calculations and the average nucleotide identity of all isolates to both and , based on whole-genome sequences, also confirmed sp. nov. as a novel species within the complex. Molecular analyses clearly demonstrated that strains MSMB43 , MSMB121, and MSMB122 belong to a novel species for which the name sp. nov. is proposed, with the type strain MSMB43 (American Type Culture Collection BAA-2767; Belgian Co-ordinated Collections of Microorganisms LMG 29471; DDBJ accession numbers CP013380 to CP013382). is a soil-dwelling bacterium and the causative agent of melioidosis. The genus consists of a diverse group of species, with the closest relatives of referred to as the complex. A proposed novel species, sp. nov., was isolated from a bore water sample from the Northern Territory in Australia. sp. nov. is phylogenetically distinct from and other members of the complex, making it the fifth member of this important group of bacteria.