Evaluation of MODS assay for rapid detection of Mycobacterium tuberculosis resistance to second-line drugs in a tertiary care tuberculosis hospital in China.

In this study we evaluated the performance of microscopic observation drug susceptibility (MODS) assay for rapid detection of Mycobacterium tuberculosis resistance to second-line drugs. 246 multidrug-resistant M. tuberculosis clinical isolates were used to compare MODS with the agar proportion method for rapid detection of resistance to 8 second-line drugs: ofloxacin, amikacin, kanamycin, capreomycin, ethionamide, cycloserine, ciprofloxacin and para-aminosalicylic acid. The sensitivity of the MODS for different drugs ranged from 88.1% to 100%, whereas the specificity ranged from 92.3% to 100%. Results for MODS assay were obtained in a median time of 7 days (range 5-18). Thus MODS assay could be used as a fast, reliable and inexpensive method for detection of M. tuberculosis resistance to second-line drugs in resource-limited settings.