This study was conducted as a retrospective matched case−control study from a prospective cohort of 8424 newly registered pulmonary TB patients who received treatment in the outpa-tient department of the TB clinic at the CCIT from January 2007 to December 2013. Cases were patients with pulmonary MDR-TB. Pulmonary MDR-TB was defined as sputum culture showing M. tuberculosis and where DST revealed drug-resistance to both INH and RMP [35]. Controls were pulmonary TB patients with sputum culture showing M. tuberculosis and where DST revealed drug-sensitivity to all four first-line anti-TB drugs, i.e., INH, RMP, EMB, and SM.