title: A horizontal gene transfer event defines two distinct groups within Burkholderia pseudomallei that have dissimilar geographic distributions.
abstract: Burkholderia pseudomallei is the etiologic agent of melioidosis. Many disease manifestations are associated with melioidosis, and the mechanisms causing this variation are unknown; genomic differences among strains offer one explanation. We compared the genome sequences of two strains of B. pseudomallei: the original reference strain K96243 from Thailand and strain MSHR305 from Australia. We identified a variable homologous region between the two strains. This region was previously identified in comparisons of the genome of B. pseudomallei strain K96243 with the genome of strain E264 from the closely related B. thailandensis. In that comparison, K96243 was shown to possess a horizontally acquired Yersinia-like fimbrial (YLF) gene cluster. Here, we show that the homologous genomic region in B. pseudomallei strain 305 is similar to that previously identified in B. thailandensis strain E264. We have named this region in B. pseudomallei strain 305 the B. thailandensis-like flagellum and chemotaxis (BTFC) gene cluster. We screened for these different genomic components across additional genome sequences and 571 B. pseudomallei DNA extracts obtained from regions of endemicity. These alternate genomic states define two distinct groups within B. pseudomallei: all strains contained either the BTFC gene cluster (group BTFC) or the YLF gene cluster (group YLF). These two groups have distinct geographic distributions: group BTFC is dominant in Australia, and group YLF is dominant in Thailand and elsewhere. In addition, clinical isolates are more likely to belong to group YLF, whereas environmental isolates are more likely to belong to group BTFC. These groups should be further characterized in an animal model.
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5640, USA.
authors.forename: Apichai
authors.initials: A
authors.lastname: Tuanyok
authors.forename: Raymond K
authors.initials: RK
authors.lastname: Auerbach
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Brettin
authors.forename: David C
authors.initials: DC
authors.lastname: Bruce
authors.forename: A Christine
authors.initials: AC
authors.lastname: Munk
authors.forename: J Chris
authors.initials: JC
authors.lastname: Detter
authors.forename: Talima
authors.initials: T
authors.lastname: Pearson
authors.forename: Heidie
authors.initials: H
authors.lastname: Hornstra
authors.forename: Rasana W
authors.initials: RW
authors.lastname: Sermswan
authors.forename: Vanaporn
authors.initials: V
authors.lastname: Wuthiekanun
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Currie
authors.forename: Paul
authors.initials: P
authors.lastname: Keim
authors.forename: David M
authors.initials: DM
authors.lastname: Wagner
mesh_terms: D001315:Australia / Q000453:epidemiology; D016957:Burkholderia pseudomallei / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D002876:Chromosomes, Bacterial / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D005838:Genotype; D006801:Humans; D008554:Melioidosis / Q000453:epidemiology / Q000382:microbiology; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D005810:Multigene Family; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D026801:Synteny; D013785:Thailand / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial