Genomic deletions classify the Beijing/W strains as a distinct genetic lineage of Mycobacterium tuberculosis.
Beijing/W strains of Mycobacterium tuberculosis are geographically widespread and hypervirulent. To enhance our understanding of their origin and evolution, we sought phylogenetically informative large sequence polymorphisms (LSPs) within the Beijing/W family. Comparative whole-genome hybridization of Beijing/W strains revealed 21 LSPs, 7 of which were previously unreported. We show that some of these LSPs are unique event polymorphisms that can be used to define and subdivide the Beijing/W family. One LSP (RD105) was seen in all Beijing/W strains and thus serves as a useful marker for the identification of this family of strains. Additional LSPs (RD142, RD150, and RD181) further divided this family into four monophyletic subgroups, demonstrating a deeper population structure than previously appreciated. All Beijing/W strains were also observed to have an intact pks15/1 gene that is involved in the biosynthesis of a phenolic glycolipid, a putative virulence factor. A simple PCR assay using these Beijing/W strain-defining deletions will facilitate molecular epidemiological studies and may assist in the identification of the molecular basis of phenotypes associated with this important lineage of M. tuberculosis.
Tsolaki
Anthony G
AG
Division of Infectious Diseases and Geographic Medicine, Stanford University Medical Center, Stanford, California 94305, USA. a.tsolaki@imperial.ac.uk
Gagneux
Sebastien
S
Pym
Alexander S
AS
Goguet de la Salmoniere
Yves-Olivier L
YO
Kreiswirth
Barry N
BN
Van Soolingen
Dick
D
Small
Peter M
PM
D001483:Base Sequence; D016680:Genome, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic; D017384:Sequence Deletion