Resazurin Microtiter Assay Plate method for detection of susceptibility of multidrug resistant Mycobacterium tuberculosis to second-line anti-tuberculous drugs

Background: Many developed countries need a diagnostic test that is accurate, rapid, and economical in detecting multidrug-resistant tuberculosis. This study aims to evaluate Resazurin Microtiter Assay Plate in detecting susceptibilities of multidrug resistant Mycobacterium tuberculosis to second line anti tuberculous drugs. Methods: Susceptibility of multidrug resistant M. tuberculosis was evaluated against 5 second line anti tuberculous drugs by the colorimetric method using the Resazurin Microtiter Assay Plate Testing (REMA). Results: Drug susceptibility testing for the second-line drugs was performed for 34 MDR M. tuberculosis isolates isolated from 40 sputum samples. Results of REMA were available after 8 days of incubation. The agreement between the two tests for para-aminosalicylic acid, ethionamide, ofloxacin, kanamycin monosulfate and cycloserine was found to be 97.05%, 94.11%, 97.05%, 97.05% and 100%, respectively. The efficacy of REMA plate assay for PAS, ETH, OFX, KAN and CYL was 97.05%, 94.11%, 97.05%, 97.05% and 100%, respectively. Conclusion: Resazurin test was found to be reliable, simple to perform for the rapid detection of anti-tuberculous drug resistance and economically inexpensive. (C) 2013 The Egyptian Society of Chest Diseases and Tuberculosis. Production and hosting by Elsevier B.V.