Authors: Rodrigues, C.1; Jani, J.2; Shenai, S.1; Thakkar, P.1; Siddiqi, S.3; Mehta, A.1
Source: The International Journal of Tuberculosis and Lung Disease, Volume 12, Number 12, December 2008 , pp. 1449-1455(7)
Publisher: International Union Against Tuberculosis and Lung Disease
OBJECTIVE: To establish the critical test concentrations for seven second-line anti-tuberculosis drugs in the Bactec Mycobacterial Growth Indicator Tube (MGIT) 960 TB system and to evaluate its efficacy compared to the Bactec 460 TB system.
DESIGN: This study was carried out in three phases. In Phase I, pan-susceptible strains were tested to establish the minimum inhibitory concentration; in Phase II, mostly resistant strains were tested to determine a critical test concentration; and in Phase III, actual clinical isolates were tested to validate the optimal critical concentrations established in Phases I and II.
RESULTS: The critical concentrations established for seven second-line drugs with the Bactec MGIT 960 system are amikacin 1.0 μg/ml, capreomycin 2.5 μg/ml, kanamycin 2.5 μg/ml, ofloxacin 2.0 μg/ml, moxifloxacin 1.0 μg/ml, ethionamide 5.0 μg/ml and para-amino salicylic acid 4.0 μg/ml.
CONCLUSION: The Bactec MGIT 960 System is an accurate and reliable method for rapid drug susceptibility testing (DST) of Mycobacterium tuberculosis against second-line drugs. In the present study, few of the strains were resistant to fluoroquinolones and further DST for this group is required.
Keywords: drug susceptibility testing; MGIT 960; India
Document Type: Regular paper
Affiliations: 1: Department of Microbiology, P D Hinduja National Hospital and Medical Research Centre Tertiary Care Hospital, Mumbai, India 2: Becton Dickinson Diagnostic Systems, Becton Dickinson, Mumbai, India 3: Becton Dickinson Diagnostic Systems, Sparks, Maryland, USA