Study of MTT and resazurin assays for susceptibility test to first-line anti-tuberculosis drugs / 中华检验医学杂志

ABSTRACT

Objecflve To evaluate the performance of two rapid and low-cost metheds(MTT test,and rosazurin mierotitre assay)for the detection of resistance to first-line drugs in Mycobacterium tuberculosis.Methods sixty-four Myeobaeterium tuberculosis clinical isohtes were tested by the MTT test and the rosazuxin microtitre assay(REMA)respectively,and the results were compared with those obtained with the absolute concentration method on L(o)wenstein Jensen medium.Results The MTT test and the resazurin microtitre assay showed a good agreement compared with the absolute concentration method for all first-line drugs tested.The sensitibity,specificity and accuracy of the MTT test were 94.8%,96.0%,95.3%,for RFP;93.8%,93.8%,93.8% for INH;92.9%,96.O%,95.3% for EMB,90.6%,87.5%,89.1% for SM,respectively.The sensitivity,specificity and accuracy of the resazurin microtitre assay were 92.3%,96.0%,93.8%,for RFP;90.6%,90.6%,90.6% for INH;92.9%,94.0%,93.8% for EMB,87.5%,87.5%,87.5% for SM,respectively.The Kappa value of the MTT test and the absolute concentration method for the detection of resistance to RFP,INH,EMB,SM were 0.857,0.831,0.714,0.792.respeedvely;The Kappa value of the regazurin mierotitre assay and the absolute concentration method for the detection of resistance to RFP,INH,EMB,SM were 0.871,0.826,0.826,0.750,respectively.The Kappa value of the MTT test and the resazurin microtitre assay for the detection of resistance to RFP,INH,EMB,SM wefe 0.889,0.875.0.787,0.844,respectively.Conclusions Both MTT test and the resazurin microtitre assays are simple,rapid,low-cost and sensitive for rapid detection of resistance to first-line drugs.They could be promising methods for susceptibility assay of the first-line antituberculosis drugs in low-resource countries.