<qa>  What is the purpose of this study?The purpose of this study is to evaluate the efficacy, safety, tolerability and pharmacokinetics of bedaquiline plus PA-824 plus linezolid after 6 months of treatment option for 9 months for subjects who remain culture positive at month 4 in Subjects with either pulmonary extensively drug resistant tuberculosis XDR-TB, treatment intolerant or non-responsive multi-drug resistant tuberculosis MDR-TB. 