Multidrug-resistant Tuberculosis.

Multidrug-resistant tuberculosis (MDR-TB) threatens to become the dominant form of tuberculosis in many parts of the world because of decades of inappropriate treatment on a global scale. Infection with MDR-TB is associated with poor outcomes because of delays in treatment and the need for complex, toxic, and long medication regimens. Most cases are undetected because of technological and economic barriers to diagnosing tuberculosis and the availability of assays to test for drug resistance. Experience in treating MDR-TB is scarce. Tuberculosis was once curable, but could become a potentially untreatable infectious disease unless efforts are made to control it.