Said, Halima MohammedKock, Marleen M.Ismail, Nazir AhmedBaba, Kamaldeen A.Omar, Shaheed VallyOsman, Ayman Gassim ElaminHoosen, Anwar AhmedEhlers, Marthie Magdaleen2012-03-192012-03-192012-01Said, HM, Kock, MM, Ismail, NA, Baba, K, Omar, SV, Osman, AG, Hoosen, AA & Ehlers, MM 2012, 'Evaluation of the GenoType (R) MTBDRsl assay for susceptibility testing of second-line anti-tuberculosis drugs', International Journal of Tuberculosis and Lung Disease, vol. 16, no. 1, pp. 104-109.1027-3719 (print)1815-7920 (online)http://hdl.handle.net/2263/18471BACKGROUND: The GenoType® MTBDRsl assay (Hains, Lifesciences, Germany) is a new rapid assay for detection of resistance to second-line anti-tuberculosis drugs. METHOD: The MTBDRsl assay was evaluated on 342 MDR-TB isolates for ofloxacin (OFX), kanamycin (KAN), capreomycin (CAP) and ethambutol (EMB) resistance and results were compared to the agar proportion method. Discrepant results were tested by DNA sequencing. RESULT: The sensitivity and specificity of MTBDRsl assay was 70.3% and 97.7% for OFX, 25.0% and 98.7% for KAN, 21.2% and 98.7% for CAP and 56.3% and 56.0% for EMB, respectively. DNA sequencing identified mutation that were not detected by MTBDRsl assay including: 8/11 phenotypically OFX-resistant isolates had mutation in gyrA (2/8 had additional mutation in the gyrB gene), 1/11 had mutation only in the gyrB gene; 6/21 phenotypically KAN-resistant isolate had mutation in rrs gene; 7/26 and 20/26 phenotypically CAP-resistant isolates had mutation in the rrs and tlyA genes, respectively. CONCLUSION: The MTBDRsl assay showed a lower sensitivity as compared to previous studies. The assay performed favourably for OFX; however the assay was less sensitive for detection of KAN/CAP resistance and demonstrated low sensitivity and specificity for EMB resistance. It is recommended that the MTBDRsl assay should include additional genes to achieve a better sensitivity for all the drugs tested.enInternational Union Against Tuberculosis and Lung Disease. This article is embargoed by the publisher until July 2012.MDR-TBXDR-TBGenotype® MTBDRslDrug resistanceTuberculosis -- TreatmentMultidrug resistance -- ResearchPostprint Article