Evaluation of the BACTEC MGIT 960 SL DST Kit and the GenoType MTBDRsl Test for Detecting Extensively Drugresistant Tuberculosis Cases

Abstract

© 2017 by the Atatürk University School of Medicine. Objective: The present study aimed to evaluate the performances of the BACTEC MGIT 960 SL DST kit and the GenoType MTBDRsl test for detecting second-line antituberculosis drug resistance in Multidrugresistant TB (MDR-TB) cases. Materials and Methods: Forty-six MDR-TB strains were studied. Second-line antituberculosis drug resistances were detected using the BACTEC MGIT 960 SL DST kit and the GenoType MTBDRsl test. The Middlebrook 7H10 agar proportion method was used as the reference test. Results: The sensitivity and specificity values for the BACTEC MGIT 960 SL DST kit were both 100% for amikacin, kanamycin, capreomycin (4 µg/mL), and ofloxacin; 100% and 95.3%, respectively, for capreomycin (10 µg/mL); and 85.7% and 100%, respectively, for moxifloxacin (0.5 µg/mL). The sensitivity and specificity values for the GenoType MTBDRsl test to detect fluoroquinolone and aminoglycoside/cyclic peptide resistance were 88.9% and 100%, respectively, for ofloxacin and 85.7% and 94.9%, respectively, for moxifloxacin (0.5 µg/ mL). The accuracy of the GenoType MTBDRsl assay for kanamycin, capreomycin, ofloxacin, and moxifloxacin was lower than that of the BACTEC MGIT 960 SL DST. Conclusion: The BACTEC MGIT 960 SL DST kit and the GenoType MTBDRsl were successful in detecting second-line antituberculosis drug resistance. Preliminary results of the GenoType MTBDRsl are very valuable for early treatment decisions, but we still recommend additional BACTEC MGIT 960 SL DST kit usage in the routine evaluation of drug-resistant tuberculosis.