Molecular characteristics of rifampicin- and isoniazid-resistant Mycobacterium tuberculosis isolates from the Russian Federation.
OBJECTIVE
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.
Afanas'ev
Maxim V
MV
Research Institute for Physical-Chemical Medicine of Ministry of Public Health of Russian Federation, Malaya Pirogovskaya St, 1a, Moscow, Russia. afanasev_max@mail.ru
Ikryannikova
Larisa N
LN
Il'ina
Elena N
EN
Sidorenko
Sergey V
SV
Kuz'min
Aleksey V
AV
Larionova
Elena E
EE
Smirnova
Tat'yana G
TG
Chernousova
Larisa N
LN
Kamaev
Eugeny Yu
EY
Skorniakov
Sergey N
SN
Kinsht
Vladimir N
VN
Cherednichenko
Andrey G
AG
Govorun
Vadim M
VM
D000995:Antitubercular Agents / Q000494:pharmacology*; D003062:Codon / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012293:Rifampin / Q000494:pharmacology*; D012426:Russia / Q000453:epidemiology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014376:Tuberculosis / Q000453:epidemiology / Q000235:genetics* / Q000382:microbiology*
D000995:Antitubercular Agents; D003062:Codon; D004269:DNA, Bacterial; D007538:Isoniazid; D012293:Rifampin