Инфекция и иммунитет (Mar 2017)

CHARACTERIZATION OF MYCOBACTERIUM TUBERCULOSIS STRAINS (A 15-YEAR SURVEY IN LENINGRAD REGION, RUSSIA)

  • A. A. Vyazovaya,
  • V. V. Vetrov,
  • L. V. Lyalina,
  • I. V. Mokrousov,
  • N. S. Solovieva,
  • V. Yu. Zhuravlev,
  • B. I. Vishnevskiy,
  • O. V. Narvskaya

DOI
https://doi.org/10.15789/2220-7619-2017-1-34-40
Journal volume & issue
Vol. 7, no. 1
pp. 34 – 40

Abstract

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In the late 90-ies of XX century in Russia there was an exacerbation of the epidemic situation of tuberculosis (TB) and “explosive” increase in pathogen drug resistances. Regardless of lower incidence of pulmonary TB in recent years, the number of cases caused by multidrug-resistant (MDR) mycobacteria was increasing due to a reduction in the effectiveness of treatment. Among the 11 subjects of the North-West Federal District the Leningrad Region is leading in the number of ineffective chemotherapy outcomes in newly diagnosed bacteriologically confirmed TB cases. A specific feature of the current epidemic situation in the Leningrad Region is the prevalence (74.1% in 2014) of MDR strains among previously treated patients with pulmonary TB. The aim of the research was a comparative genotypic characterization of Mycobacterium tuberculosis strains, isolated from patients with chronic pulmonary tuberculosis in the Leningrad Region in 1999–2004 and 2010–2014. As defined by spoligotyping, the Beijing family genotype was prevailing among M. tuberculosis strains of previously treated patients from Leningrad region (76.5% in 2010–2014 versus 56.3% in 1999–2004). The proportion of other genotypes strains — LAM and T decreased from 16.7 and 12.5% to 10.3 and 2.9%, respectively. The proportion of multi-drug resistance in the studied subpopulations of the Beijing genotype strains remained virtually constant (86.5 and 88.9%). The extensive drug resistance was not observed among MDR Beijing strains in 1999–2004, whereas in 2010–2014 it reached 33.3%. MIRU-VNTR-typing (12 loci) of 68 M. tuberculosis strains revealed 20 profiles; of these, five were presented by clusters MIT1, MIT46, MIT16, MIT17, MIT571, comprising two or more strains. The largest clusters MIT16 (223325153533) and MIT17 (223325173533) included 25 (48.1%) and 21 (40.4%) apparently highly transmissible Beijing genotype strains. Previously, clinical significance and mainly epidemic pathways for MDR M. tuberculosis Beijing strains belonging to these MIRU-VNTR-types were proved in a number of Russian regions. These findings require in-depth analysis of the situation in the region studied.

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