Drug Resistant TB
Multi-drug resistant tuberculosis (MDR-TB) and extensively drug resistant tuberculosis (XDR-TB) have emerged.
MDR-TB results from an organism that is resistant to at least isoniazid and rifampin, the two most potent TB drugs.
XDR-TB is resistant to isoniazid and rifampin, any fluoroquinolone, and one or more of the second-line drugs (such as capreomycin, amikacin, or kanamycin).
Anti-TB drug resistance primarily occurs when patients do not complete their full course of treatment or when health-care providers prescribe the incorrect drug combinations, wrong duration, or incorrect dose.