Patients were adults (≥18 years of age) who had newly diagnosed, previously untreated M. tuberculosis infection, as determined by positive results on sputum smears on two occasions, with culture-confirmed susceptibility to rifampin and fluoroquinolones. Patients who were coinfected with the human immunodeficiency virus (HIV) were eligible to participate in the study if the CD4+ count was at least 250 cells per cubic millimeter and they were not already receiving antiretroviral therapy. Detailed inclusion and exclusion criteria are provided in the Supplementary Appendix. All patients provided written or witnessed oral informed consent.