Genetic characteristics of Mycobacterium tuberculosis strains, isolated among Moscow residents
Abstract number: P610
Afanasev M., Ilina E., Smirnova T., Larionova E., Kuzmin A., Andreevskaya S., Chernousova L., Govorun V.
Objectives: Moscow is the largest city of Russia with intensive migration flow (including peoples from Former Soviet Union (FSU) countries). High TB morbidity and increasing numbers of multidrug-resistance (MDR) in Russia and FSU countries call an attention to the effective preventive, prophylaxis and surveillance measures, aimed to prevent and avoid M. tuberculosis transmission and MDR spread in the community. The purposes of this study were to evaluate epidemiological diversity and MDR spreading among M. tuberculosis strains, circulated among Moscow residents.
Methods:M. tuberculosis strains (n = 115) have been randomly selected from sputum of epidemiologically unrelated TB patients, which were Moscow residents. Species identification and drug susceptibility testing to main antituberculosis drugs rifampicin (RIF) and isoniazid (INH) were performed according to the WHO recommendation protocols. Standard procedures of spoligotyping and 24-loci VNTR typing were carried out as described previously. For detect specific antimicrobial resistance SNPs minisequencing reaction followed by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) of the reaction products was used.
Results: Among 115 M. tuberculosis strains 76 (66.0%) were identified as MDR, 20 (17.4%) were susceptible to RIF and INH, and 1 (0.9%) and 18 (15.7%) were resistant either to RIF or INH, respectively.
Mutations in the RRDR of the rpoB gene were detected in 64 (64/77; 83.1%) RIF resistant strains. The Ser531Leu substitution was prevalent among them (49/64; 76.5%). Aberrations in the Ser315 codon of katG and/or in the inhA promoter region were found in 79 (84.0%) of 94 INH-resistant strains.
Strains belonged to the Beijing family were prevalent 66.0% (76/115), the other two large families (LAM and T) occurred rarer (10.4% and 8.7%, respectively). Seventy one different VNTR profiles were identified. Tree main 24-loci VNTR clusters included 34 (34/115; 29.5%) strains belonged to Beijing family. MDR-phenotype revealed more frequently among Beijing strains (59/76; 77.6%), than among other strains (17/39; 43.6%) (c-square = 13.3; p = 0.0003).
Conclusion: Obviously, Beijing family plays a significant role in the spread of MDR TB in the Moscow. Spoligotyping and 24-loci VNTR typing combination demonstrate sufficient discrimination power and may be useful for TB monitoring in Moscow region.
|Session name:||19th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Helsinki, Finland, 16 - 19 May 2009|
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