JAC Advance Access published online on April 18, 2007
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkm086
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Molecular characteristics of rifampicin- and isoniazid-resistant Mycobacterium tuberculosis isolates from the Russian Federation
1 Research Institute for Physical–Chemical Medicine of Ministry of Public Health of Russian Federation, Malaya Pirogovskaya St, 1a, 119992 Moscow, Russia 2 National Research Centre for Antibiotics, Moscow, Russia 3 Central Tuberculosis Research Institute, Russian Academy of Medical Sciences, Moscow, Russia 4 Ural Research Institute for Phthisiopulmonology, Ekaterinburg, Russia 5 Novosibirsk Tuberculosis Research Institute of Ministry of Public Health of Russian Federation, Novosibirsk, Russia
Received 6 December 2006; returned 29 January 2007; revised 9 February 2007; accepted 27 February 2007
* Corresponding author. Tel: +7-495-246-45-70; Fax: +7-495-246-45-01; E-mail: afanasev_max{at}mail.ru
Objectives: Three Mycobacterium tuberculosis genetic loci—rpoB and katG genes and the fabG1(mabA)–inhA operon promoter region—were studied to reveal the mutations associated with rifampicin and isoniazid resistance.
Methods: Four hundred and twelve isolates of M. tuberculosis from different regions of the Russian Federation were collected during 1997–2005. A matrix-assisted laser-desorption ionization–time-of-flight mass spectrometry (MALDI–TOF MS)-based minisequencing method was used for the detection of mutations.
Results: Thirteen different variants of single mutations in codons 533, 531, 526, 516, 513 and 511 of the rifampicin resistance-determining region of the rpoB gene as well as the TTG insertion in the 514a position were found among the rifampicin-resistant isolates. Single nucleotide substitutions in codons 531, 526 and 516 (64.8%, 10.3% and 7.7%, respectively) were the most prevalent mutations. Codon 526 was shown to be the most variable of all. No mutations were detected in rpoB genes for 29 (10.7%) of the rifampicin-resistant isolates. 76.9% of the isoniazid-resistant isolates carried single mutations in codon 315 of the katG gene. For another 12.9% of them, double mutations in the katG gene and the fabG1(mabA)–inhA promoter region were revealed. No mutations were detected in 8.2% of the isoniazid-resistant isolates.
Conclusions: Molecular analysis of the loci of rpoB and katG genes and the inhA promoter region of 412 M. tuberculosis clinical isolates from various parts of the Russian Federation was carried out. The new MALDI-TOF MS-based method may be used for rapid and accurate monitoring of the spread of drug resistance.
Key Words: drug resistance , tuberculosis , SNPs , MALDI–TOF mass spectrometry