Abstract: Objective To evaluate the value of nitrate reductase assay(NRA) for drug susceptibility testing of Mycobacterium tuberculosis. Method Four hundries and ninety-two Mycobacterium tuberculosis strains and 30 standard strains were determined the resistances to isoniazid,rifampin,streptomycin,and ethambutol with absolute concentration method and NRA. Results Absolute concentration method as control,NRA and absolute concentration method in accordance basically(than 95%),NRA susceptibility was more than 90% and specificity than 95%.Compare with absolute thickness law,the sensitivities of NRA for the detection of isoniazid,rifampin,streptomycin,and ethambutol resistances were 91.6%,96.5%,92.2%,90.7%,respectively.The specificities of NRA were 96.0%,98.2%,97.3%,97.3%,respectively.The accordance rates of these two Methods were 95.0%,97.9%,96.2%,96.7%,respectively. Conclusions NRA is a simple,rapid and low-cost drug susceptibility testing of Mycobacterium tuberculosis.

Key words: nitrate reductase assay, M.tuberculosis, Drug susceptibility testing