Multicenter laboratory validation of the BACTEC MGIT 960 technique for testing susceptibilities of Mycobacterium tuberculosis to classical second-line drugs and newer antimicrobials.
The BACTEC MGIT 960 system, a fully automated, nonradiometric, noninvasive system for detection and drug susceptibility testing of mycobacteria, was evaluated for the ability to test susceptibilities to second-line drugs. In this study, which was carried out in three phases (phase I, mostly susceptible strains; phase II, mostly resistant strains; phase III, final testing of the optimal drug concentrations found in phases I and II), we established the critical concentrations for seven drugs to be tested in the BACTEC MGIT 960 system compared to the BACTEC 460TB system. The critical concentrations for the seven drugs used in the MGIT 960 system are as follows: amikacin, 1.0 microg/ml; capreomycin, 2.5 microg/ml; ethionamide, 5.0 microg/ml; protionamide, 2.5 microg/ml; ofloxacin, 2.0 microg/ml; rifabutin, 0.5 microg/ml; linezolid, 1.0 microg/ml. Our results demonstrate that the BACTEC MGIT 960 system is an accurate method for rapid testing of the susceptibilities of Mycobacterium tuberculosis to second-line drugs.
Rüsch-Gerdes
Sabine
S
National Reference Center for Mycobacteria, Forschungszentrum Borstel, Parkallee 18, D-23845 Borstel, Germany. srueschg@fz-borstel.de
Pfyffer
Gaby E
GE
Casal
Manuel
M
Chadwick
Maureen
M
Siddiqi
Salman
S
D000995:Antitubercular Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D066298:In Vitro Techniques; D008826:Microbial Sensitivity Tests / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification; D011786:Quality Control
D000995:Antitubercular Agents