Comparison of Three Molecular Assays for the Detection of Rifampin Resistance in Mycobacterium tuberculosis

BackgroundRifampin (RIF) is the most important first-line antituberculosis drug, and resistance to this drug may result in treatment failures. We evaluated the diagnostic performances of recently introduced, molecular assays for the detection of RIF resistance. MethodsA total of 100 isolates (50 RIF resistant and 50 RIF susceptible) were studied. Their RIF resistances were determined by conventional drug-susceptibility test. These results were compared with those of three molecular assays: Xpert MTB/RIF assay (MTB is Mycobacterium tuberculosis), Sacace MTB Real-TM resistance, and AdvanSure MDR-TB GenoBlot assay (MDR is multidrug resisitant). ResultsSensitivities for RIF resistance detection of Xpert MTB/RIF assay, Sacace MTB Real-TM resistance, and Advansure GenoBlot assay were 94.0%, 91.8%, and 84.0%, respectively. Their specificities for RIF resistance detection were all 100%. ConclusionThree molecular assays for the detection of RIF resistance have various performances. Xpert MTB/RIF assay shows the highest sensitivity among the three molecular assays and can be an effective choice in clinical laboratories.