In vitro drug susceptibility of bedaquiline, delamanid, linezolid, clofazimine, moxifloxacin, and gatifloxacin against extensively drug -resistant tuberculosis from Beijing, China. Extensively drug-resistant tuberculosis (XDR-TB) is a deadly form of TB that can be incurable due to its extreme drug resistance. In this study, we aimed to explore the susceptibility to bedaquiline (BDQ ), delamanid (DMD), linezolid (LZD), clofazimine (CLO), moxifloxacin (MFX), and gatifloxacin (GAT) of 90 XDR-TB strains isolated from patients in China. We also describe the genetic characteristics of XDR-TB isolates with acquired drug resistance. Resistance to MFX, GAT, LZD, CLO, DMD, and BDQ was found in 82 (91.1%), 76 (84.4%), 5 (5.6%), 5 (5.6%), 4 (4.4%), and 3 (3.3%) isolates among the XDR-TB strains