Acquired Resistance to Bedaquiline and Delamanid in Therapy for Tuberculosis

Treatment of multidrug-resistant Mycobacterium tuberculosis is a challenge. This letter describes the emergence of resistance to new therapies, bedaquiline and delamanid. To the Editor: Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) are an increasing public health threat. 1 Bedaquiline and delamanid are two drugs that were recently approved by the Food and Drug Administration for treatment of MDR-TB and XDR-TB. 2 Here we describe the stepwise amplification of drug resistance in a patient who had emigrated from Tibet to Switzerland in December 2010 and who presented to a Swiss hospital with preextensively drug-resistant tuberculosis at that time. Genome sequencing revealed that the initial Mycobacterium tuberculosis isolate harbored nine mutations in genes associated with resistance to seven drugs (Figure 1, and the Supplementary Appendix, . . .