The study population will be drawn from subjects at the National Masan Tuberculosis Hospital (NMTH), Changwon, Republic of Korea. Subjects presenting at NMTH who have been previously treated with first-line agents and who are multi-drug resistant (MDR), defined as having TB isolates that are resistant to at least isoniazid and rifampicin, and are therefore eligible for second-line antituberculous drug therapy will be included.