Evaluation of the GenoType MTBDRplus and MTBDRsl for the detection of drug-resistant Mycobacterium tuberculosis on isolates from Beijing, China Jiyong Jian,1–3 Xinyu Yang,4 Jun Yang,5 Liang Chen1–3 1Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, China; 2Peking University Ninth School of Clinical Medicine, Beijing, China; 3Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China; 4Central Laboratory, Beijing Research Institute for Tuberculosis Control, Beijing, China; 5Department of Sterilized supplying, PLA 306 Hospital, Beijing, China Background: The incidence of tuberculosis (TB), especially multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB), continues to increase alarmingly worldwide. Molecular line probe assays (LPAs) are endorsed by the World Health Organization for the fast detection of MDR-TB and XDR-TB. The aim of this study was to evaluate the performance of LPAs in China. Methods: We analyzed MDR-TB and XDR-TB in 96 isolates from Beijing by using culture-based drug susceptibility testing (DST) and LPAs to compare the detection rate of the two methods. Results: Compared to phenotypic DST, the GenoType® MTBDRplus and MTBDRsl, respectively, showed a sensitivity of 98.7% and a specificity of 88.9% for detection of rifampicin resistance, 82.1% and 94.4% for isoniazid, 89.7% and 94.4% for levofloxacin, 60.0% and 98.7% for amikacin/capreomycin, and 57.5% and 98.2% for ethambutol. The sensitivity and specificity of LPAs, respectively, were 80.8% and 100% for MDR-TB and 50.0% and 97.6% for XDR-TB. Mutations in codon S531L of the rpoB gene and S315T1 of the KatG gene were dominated in MDR-TB strains. The most frequently observed mutations were in codon A90V of the gyrA gene, A1401G of the rrs gene, and M306V of the embB gene, according to the MTBDRsl results. Conclusion: Our study showed that, in combination with phenotypic DST, application of the LPAs might be an efficient and reliable supplementary DST assay for rapid susceptibility screening of MDR-TB and XDR-TB. Using LPAs in countries with high MDR/XDR burden allows for appropriate and timely treatment, which will reduce transmission rates and morbidity, and improve treatment outcomes in patients. Keywords: Mycobacterium tuberculosis, MDR-TB, XDR-TB, line probe assay, phenotypic drug susceptibility testing