title: Molecular detection of fluoroquinolone resistance-associated gyrA mutations in ofloxacin-resistant clinical isolates of Mycobacterium tuberculosis from Iran and Belarus.
abstract: Detection of mutations in the quinolone resistance-determining region (QRDR) of the gyrA gene could determine resistance to fluoroquinolone antituberculosis drugs. The aim of this study was to detect mutations in QRDRs.
  
  
  
  From 184 clinical isolates of Mycobacterium tuberculosis, ofloxacin resistance was proven in 42 isolates using the proportion method. The molecular basis of resistance to ofloxacin were investigated by the determination of mutations in the QRDR region of the gyrA gene. Extracted DNA fragments of 194bp from the gyrA gene were amplified and an automatic DNA sequencer was used for the sequencing process.
  
  
  
  Molecular genetic analysis of 42 resistant M. tuberculosis strains demonstrated that they belong to Principal Genetic Group (PGG) 1 in 19 cases (45.2±10.9%), to PGG2 in 15 cases (35.7±10.5%), and to PGG3 in eight cases (19.0±8.4%). Isolates from PGG1 were dominant among resistant isolates (P<.05). It was found that 24 (57%) resistant isolates carried mutations at codon 94 with five different amino acid changes: D94A (n=11), D94G (n=3), D94T (n=4), D94A (n=4), and D94Y (n=2). The remaining 18 (43%) isolates had mutations in codon A90V (GCG→GTG) and S91P (TCG→CCG). Five isolates had two mutations in codons 90 and 94. There was no difference between mutations at these two codons in resistant isolates of the two countries (P<.001). There was no polymorphism observed in codon 95 in any of the ofloxacin-susceptible isolates.
  
  
  
  It was concluded that the determination of nucleotide sequences of QRDRs can be used as a molecular test for the rapid detection of ofloxacin resistance. Furthermore, frequencies in gyrA codons in Belarus and Iran were similar, therefore it is not of geographical concern for the two countries.
authors.affiliation: Infectious Diseases Research Center (IDRC), Arak University of Medical Sciences, Arak, Iran. Electronic address: mmatinam81@yahoo.com.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Arjomandzadegan
authors.affiliation: Research Institute for Epidemiology and Microbiology, Minsk, Belarus.
authors.forename: Leonid
authors.initials: L
authors.lastname: Titov
authors.affiliation: Mycobacteriology Research Centre (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Parissa
authors.initials: P
authors.lastname: Farnia
authors.affiliation: Molecular Microbiology Research Center, Shahed University, Tehran, Iran.
authors.forename: Parviz
authors.initials: P
authors.lastname: Owlia
authors.affiliation: Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Ranjbar
authors.affiliation: Mycobacteriology Research Centre (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Sheikholeslami
authors.affiliation: Institute for Pulmonology and Phthisiology, Minsk, Belarus.
authors.forename: Larissa
authors.initials: L
authors.lastname: Surkova
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D027081:DNA Gyrase / Q000235:genetics*; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology*; D060005:Genotyping Techniques / Q000379:methods*; D006801:Humans; D007492:Iran; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D015242:Ofloxacin / Q000494:pharmacology; D002094:Republic of Belarus; D017422:Sequence Analysis, DNA / Q000379:methods
chemical_list: D000995:Antitubercular Agents; D024841:Fluoroquinolones; D015242:Ofloxacin; D027081:DNA Gyrase
keywords: Mutation; Mycobacterium tuberculosis; Ofloxacin; Resistance; gyrA