Patient description: Patient A is a 30-year-old male who was admitted to the hospital after 10 days of cough, profuse nocturnal sweating and loss of appetite. He had traveled to India 1 months ago and has not any positive history of TB vaccination. He is a previously healthy man, working as an engineer in a high tech company. He doesn't smoke o use any illicit drugs. He was febrile (38 c) with heart rate of 115 b/min, respiratory rate of 22, BP of 125/75 mmHg and O2 sat of 97%. Chest X-ray showed infiltrate in the middle of left lung with diameter of 1.8 cm with signs of cavitation. The sputum smear revealed positive sputum culture for Mycobacterium tuberculosis which are sensitive of the first-line TB drugs (isoniazid, streptomycin, rifampicin and ethambutol). Lab study is reported bellow: Hgb: 13 g/dl WBC: 14000 /mm3 Plt: 300000 /ml AST: 13 U/L ALT: 15 U/L Alk P: 53 U/L Bill total: 0.6 mg/dl Na: 137 mEq/l K: 4 mEq/l Creatinine: 0.5 mg/dl BUN: 10 mg/dl ESR: 120 mm/hr

Clinical trial eligibility criteria: eligible ages (years): 2.0-999.0,  Tuberculosis Males or nonpregnant, non-nursing females > 2 years old Tuberculin (PPD) skin test reactors at high risk for developing TB but without evidence of active TB. High-risk reactors are defined as: 1. Household and other close contacts of persons with culture-confirmed TB who are TST-positive as part of a contact investigation conducted within two years of the date of enrollment. Close contact is defined as > 4 hours in a shared airspace during a one-week period. Among close contacts, a positive TST is defined as > 5 mm induration after 5 TU of PPD placed intradermally using the Mantoux technique. 2. TST converters--converting from a documented negative to positive TST within a two-year period. This is defined as persons with a tuberculin skin test of > 10 mm within two years of a nonreactive test or persons with an increase of > 10 mm within a two-year period. 3. HIV-seropositive, TST positive (> 5 mm induration) persons. 4. Persons with > 2 cm2 of pulmonary parenchymal fibrosis on chest X-ray, no prior history of TB treatment, > 5 mm induration on TST, and 3 sputum cultures negative for M. tuberculosis on final report HIV-seropositive close contacts of persons with culture-confirmed TB, regardless of TST status. In addition, HIV-seropositive close contacts of persons with culture-confirmed TB who have a documented history of completing an adequate course of treatment for active TB or latent TB infection, are also eligible Willing to provide signed informed consent, or parental consent and participant assent  Current confirmed culture-positive or clinical TB Suspected TB (as defined by the site investigator) Tuberculosis resistant to isoniazid or rifampin in the source case A history of treatment for > 14 consecutive days with a rifamycin or > 30 consecutive days with INH during the previous 2 years A documented history of a completing an adequate course of treatment for active TB or latent TB infection in a person who is HIV-seronegative History of sensitivity/intolerance to isoniazid or rifamycins Serum aminotransferase aspartate (AST, SGOT) > 5x upper limit of normal among persons in whom AST is determined Pregnant or nursing females Persons currently receiving or planning to receive HIV-1 protease inhibitors or nonnucleoside reverse transcriptase inhibitors in the first 90 days after enrollment Weight < 10.0 kg