Comparative evaluation under routine conditions of the nitrate reduction assay, the proportion assay and the MGIT 960 assay for drug susceptibility testing of clinical isolates of Mycobacterium tuberculosis

摘要

The performance of the nitrate reductase assay (NRA) was compared with the proportion method (PM) onLowenstein-Jensen medium and the BACTEC MGIT960 assay under routine conditions using 160 clinical isolatesof Mycobacterium tuberculosis with a high proportion of resistant strains. The mean time to obtain results was 8.8days and the overall agreements between NRA and PM and NRA and M960 were 95% and 94%, respectively. NRAwas easy to perform and represents a useful tool for the rapid screening of drug-resistant Mycobacterium tuberculosis strains inlow-resource countries.