Comparison of three molecular assays for the detection of rifampin resistance in mycobacterium tuberculosis

Abstract

Background: Rifampin (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. Methods: A 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). Results: Sensitivities 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%. Conclusion: Three 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.