ORIGINAL: In the induction phase, patients enrolled in "drug-susceptible" areas (defined as metropolitan areas with a resistance rate for isoniazid therapy of less than 10 percent) receive four drugs: isoniazid (plus pyridoxine), rifampin, pyrazinamide, and ethambutol. Patients enrolled in "drug-resistant" areas (resistance rate for isoniazid of 10 percent or higher) receive the four-drug regimen with or without a fifth drug, levofloxacin. After 8 weeks of induction, patients with multi-drug resistance are removed from study regimens; all other patients enter a continuation phase. Pansusceptible patients (showing susceptibility to all first-line anti-TB drugs) receive two study drugs for an additional 18 or 31 weeks; patients with isoniazid-resistant (or intolerant) TB receive two or three study drugs for an additional 44 weeks, while those with rifampin-resistant TB receive two or three study drugs for an additional 70 weeks. Patients are evaluated every 2 weeks in the induction phase and every 12 weeks in the continuation phase. Minimum follow-up is 2 years.