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

BackgroundMany 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.MethodsSusceptibility 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).ResultsDrug 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.ConclusionResazurin test was found to be reliable, simple to perform for the rapid detection of anti-tuberculous drug resistance and economically inexpensive.