title: Determination of critical concentrations of moxifloxacin and gatifloxacin for drug susceptibility testing of Mycobacterium tuberculosis in the BACTEC MGIT 960 system.
abstract: OBJECTIVE
  To determine critical concentrations of moxifloxacin and gatifloxacin for rapid evaluation of drug susceptibility of Mycobacterium tuberculosis in Middlebrook 7H9 broth using the automated system BACTEC™ MGIT™ 960.
  
  
  METHODS
  In total we studied 152 strains. Critical concentrations of moxifloxacin and gatifloxacin in the BACTEC™ MGIT™ 960 and on Lowenstein-Jensen medium were determined using a panel of 68 strains. The proportion method on Middlebrook 7H10 medium was used as a reference method. Drug susceptibility testing against fluoroquinolones was done for the other 84 strains using the established critical concentrations. The gyrA and gyrB genes of all strains were studied by molecular tests.
  
  
  RESULTS
  The critical concentrations determined for moxifloxacin and gatifloxacin were 0.25 mg/L in the BACTEC™ MGIT™ 960 system and 0.75 mg/L on Lowenstein-Jensen medium (absolute concentration method).
  
  
  CONCLUSIONS
  The moxifloxacin and gatifloxacin critical concentrations that we have established are reliable for rapid drug susceptibility testing in the BACTEC™ MGIT™ 960.
authors.affiliation: Moscow Scientific and Clinical Antituberculosis Center of Moscow Government Health Department, Moscow, 107014 Stromynka 10, Russia.
authors.forename: Yu
authors.initials: Y
authors.lastname: Isaeva
authors.forename: A
authors.initials: A
authors.lastname: Bukatina
authors.forename: L
authors.initials: L
authors.lastname: Krylova
authors.forename: E
authors.initials: E
authors.lastname: Nosova
authors.forename: M
authors.initials: M
authors.lastname: Makarova
authors.forename: A
authors.initials: A
authors.lastname: Moroz
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D057205:Automation, Laboratory / Q000379:methods; D001372:Aza Compounds / Q000494:pharmacology*; D003470:Culture Media / Q000737:chemistry; D024841:Fluoroquinolones / Q000494:pharmacology*; D000077734:Gatifloxacin; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D000077266:Moxifloxacin; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D011804:Quinolines / Q000494:pharmacology*
chemical_list: D000995:Antitubercular Agents; D001372:Aza Compounds; D003470:Culture Media; D024841:Fluoroquinolones; D011804:Quinolines; D000077734:Gatifloxacin; D000077266:Moxifloxacin
keywords: drug resistance; fluoroquinolones; microbiology; rapid tuberculosis diagnostics