Drug-resistant tuberculosis in children.

Drug-resistant tuberculosis (TB), and especially multidrugresistant (MDR) TB (i.e. resistance to isoniazid and rifampicin with or without resistance to other drugs) or extensively drug-resistant (XDR) TB (i.e. MDR resistance plus resistance to the fluoroquinolones and one of the second-line injectables - kanamycin, amikacin or capreomycin), has very important implications for affected children and the TB control programme.