The World Health Organization recommends to use bedaquiline (BDQ) to formulate efficacious combination regimens against multidrug-resistant tuberculosis (MDR-TB). Here, we firstly report a case series of MDR-TB patients treated with BDQ, who experienced sputum culture reconversion due to emergence of nontuberculous mycobacteria (NTM) infections.
A multicentre case series were established including patients who started treatment for laboratory-confirmed MDR-TB from January 1, 2018 to March 31, 2020. We included patients with positive cultures, which had no expression of tuberculosis-specific MPT64 protein. The multilocus sequence analysis was used to perform rapid species identification. The susceptibility to BDQ was detected using the Thermo Fisher frozen microtiter plates by the laboratory staffs of Beijing Chest Hospital uniformly.
Of 286 patients receiving BDQ-regimens included in this study, the emergence of NTM isolations were reported in nine (3.1%) patients. After exposure to BDQ, seven out of nine patients achieved culture conversion by four weeks. The median time of reported NTM infection was 12 weeks (range: 4-24 weeks). Of these, seven were rapidly growing mycobacteria, and two were slowly growing mycobacteria. The most frequent NTM species was M. abscessus (five isolates), followed by M. fortuitum (two isolates), M. avium (one isolate), and M. intracellulare (one isolate), respectively. In addition, three patients showed resistance to BDQ at baseline.
In conclusion, our results demonstrate the emergence of novel NTM populations for MDR-TB patients during BDQ therapy. The dramatically rapid development of NTM infections underlines the need of systematic species identification during follow-up period.

Copyright © 2020. Published by Elsevier Ltd.