Bernice Meng Qi SimNarisara ChantratitaWen Fong OoiTannistha NandiRyan TewheyVanaporn WuthiekanunJanjira ThaipadungpanitSarinna TumapaPramila AriyaratneWing Kin SungXiao Hui SemHui Hoon ChuaKalpana RamnarayananChi Ho LinYichun LiuEdward J. FeilMindy B. GlassGladys TanSharon J. PeacockPatrick TanGenome Institute of SingaporeMahidol UniversityScripps Research InstituteNational University of SingaporeNational Cancer Centre, SingaporeDSO National LaboratoriesUniversity of BathCenters for Disease Control and PreventionUniversity of CambridgeDuke-NUS Graduate Medical School Singapore2018-09-242018-09-242010-08-27Genome Biology. Vol.11, No.1 (2010)1474760X147475962-s2.0-77955975412https://repository.li.mahidol.ac.th/handle/123456789/28467© 2006 Sim et al. Background: Burkholderia thailandensis is a non-pathogenic environmental saprophyte closely related to Burkholderia pseudomallei, the causative agent of the often fatal animal and human disease melioidosis. To study B. thailandensis genomic variation, we profiled 50 isolates using a pan-genome microarray comprising genomic elements from 28 Burkholderia strains and species. Results: Of 39 genomic regions variably present across the B. thailandensis strains, 13 regions corresponded to known genomic islands, while 26 regions were novel. Variant B. thailandensis isolates exhibited isolated acquisition of a capsular polysaccharide biosynthesis gene cluster (B. pseudomallei-like capsular polysaccharide) closely resembling a similar cluster in B. pseudomallei that is essential for virulence in mammals; presence of this cluster was confirmed by whole genome sequencing of a representative variant strain (B. thailandensis E555). Both wholegenome microarray and multi-locus sequence typing analysis revealed that the variant strains formed part of a phylogenetic subgroup distinct from the ancestral B. thailandensis population and were associated with atypical isolation sources when compared to the majority of previously described B. thailandensis strains. In functional assays, B. thailandensis E555 exhibited several B. pseudomallei-like phenotypes, including colony wrinkling, resistance to human complement binding, and intracellular macrophage survival. However, in murine infection assays, B. thailandensis E555 did not exhibit enhanced virulence relative to other B. thailandensis strains, suggesting that additional factors are required to successfully colonize and infect mammals. Conclusions: The discovery of such novel variant strains demonstrates how unbiased genomic surveys of nonpathogenic isolates can reveal insights into the development and emergence of new pathogenic species.Mahidol UniversityAgricultural and Biological SciencesBiochemistry, Genetics and Molecular BiologyArticleSCOPUS10.1186/gb-2010-11-8-r89