title: Mycobacterium tuberculosis Beijing genotype in Russia: in search of informative variable-number tandem-repeat loci.
abstract: The Beijing genotype is a globally spread lineage of Mycobacterium tuberculosis. In Russia, these strains constitute half of the local population of M. tuberculosis; they are associated with multidrug resistance and show increased transmissibility. Here, we analyzed traditional and new markers for the rapid and simple genotyping of the Beijing strains. A representative sample of 120 Beijing genotype strains was selected from a local IS6110-restriction fragment length (RFLP) database at the St. Petersburg Pasteur Institute. These strains were subjected to variable-number tandem-repeat (VNTR) typing using 24 loci of a newly proposed format and three hypervariable (HV) loci (QUB-3232, VNTR-3820, and VNTR-4120). Ten of the 27 VNTR loci were monomorphic, while five loci, MIRU26, QUB-26, QUB-3232, VNTR-3820, and VNTR-4120, were the most polymorphic (Hunter Gaston index, >0.5). VNTR typing allowed us to differentiate between two large IS6110-RFLP clusters known to be prevalent across the entire country (clusters B0/W148 and A0) and identified in 27 and 23% of strains, respectively, in the Beijing genotype database. The B0/W148 strains were grouped closely in the VNTR dendrogram and could be distinguished by a characteristic signature of the loci MIRU26 and QUB-26. Consequently, this clinically important IS6110-RFLP variant, B0/W148, likely presents a successful clonal group within the M. tuberculosis Beijing lineage that is widespread in Russia. To conclude, the IS6110-RFLP method and VNTR typing using a reduced set of the most polymorphic loci complement each other for the high-resolution epidemiological typing of the M. tuberculosis Beijing genotype strains circulating in or imported from Russia.
authors.affiliation: Laboratory of Molecular Microbiology, St. Petersburg Pasteur Institute, St. Petersburg 197101, Russia. igormokrousov@yahoo.com
authors.forename: Igor
authors.initials: I
authors.lastname: Mokrousov
authors.forename: Olga
authors.initials: O
authors.lastname: Narvskaya
authors.forename: Anna
authors.initials: A
authors.lastname: Vyazovaya
authors.forename: Julie
authors.initials: J
authors.lastname: Millet
authors.forename: Tatiana
authors.initials: T
authors.lastname: Otten
authors.forename: Boris
authors.initials: B
authors.lastname: Vishnevsky
authors.forename: Nalin
authors.initials: N
authors.lastname: Rastogi