Treatment of multidrug-resistant and extensively drug-resistant tuberculosis: current status and future prospects

Drug resistance in Mycobacterium tuberculosis arises from the man-made selection of mutants that result from spontaneous chromosomal alterations. Preventing the development of drug-resistant TB through a good control program based on directly observed treatment, short-course, is of paramount importance. Established multidrug-resistant (MDR)-TB requires alternative specific chemotherapy, comprising drugs with higher cost and greater toxicity delivered on a programmatic basis. The development of new anti-TB drugs would help to prevent and treat MDR-TB. Notably, moxifloxacin and gatifloxacin are being tested for shortening treatment in Phase III trials, while three novel compounds, TMC-207, OPC-67683 and PA-824 are in Phase II studies for both drug-susceptible and drug-resistant disease. The roles of surgery and immunotherapy in the management of MDR-TB require further evaluation. The recent emergence of extensively drug-resistant TB poses a serious challenge to the global control of TB. In order to combat extensively drug-resistant TB, strengthening of directly observed treatment, short-course and drug-resistance programs, alongside other strategies, including the development of newer diagnostics and drugs, is mandatory.