Among TB patients, there has been an increase in progressive disease due to the emergence of antimycobacterial drug-resistant strains of Mycobacterium tuberculosis. Failure to identify patients at high risk for MDRTB increases the hazard for both treatment failure and development of resistance to additional therapeutic agents. Efforts to improve survival in patients with MDRTB will depend on improved methods of assessing the risk of acquisition of MDRTB and identifying drug susceptibility patterns in a timely fashion.

Patients are asked a series of questions to determine epidemiologic factors that may be predictive of MDRTB. Patients who are determined to be at low risk for MDRTB will be referred to another TB treatment protocol (ACTG 222), if appropriate. Patients suspected of having primary or acquired MDRTB or those with confirmed MDRTB will be offered a regimen of anti-TB therapy from a hierarchically ordered list of drugs, based on the patient's resistance status (suspect primary MDRTB, suspect acquired MDRTB, or confirmed MDRTB). The hierarchical list is as follows: isoniazid, rifampin, ethambutol, streptomycin, levofloxacin, ethionamide, cycloserine, capreomycin, aminosalicylic acid, and clofazimine. Treatment will be administered daily for at least 6 months, then on an intermittent schedule at the clinician's discretion. Patients with confirmed MDRTB (defined as known resistance to at least isoniazid and rifampin within 6 months prior to study entry) will receive a minimum of 18 months of treatment following sputum culture conversion. Follow-up is performed every 4 weeks for 8 weeks, and then every 8 weeks.