Directly observed treatment, short-course strategy and multidrug-resistanttuberculosis: are any modifications required?

Multidrug-resistant tuberculosis (MDRTB) should be defined as tuberculosis with resistance to at least isoniazid and rifampicin because these drugs ar e the cornerstone of short-course chemotherapy, and combined isoniazrd and rifampicin resistance requires prolonged treatment with second-line agents. Short-course chemotherapy is a key ingredient in the tuberculosis control strategy known as directly observed treatment short-course (DOTS). Far popu lations in which multidrug-resistant tuberculosis is endemic, the outcome o f the standard short-course chemotherapy regimen remains uncertain. Unaccep table failure rates have been reported and resistance to additional agents may be induced. As a consequence there have been calls for well-functioning DOTS programmes to provide additional services in areas with high rates of multidrug-resistant tuberculosis. These "DOTS-plus for MDRTB programmes" m ay need to modify all five elements of the DOTS strategy: the treatment may need to be individualized rather than standardized; laboratory services ma y need to provide facilities for on-site culture and antibiotic susceptibil ity testing; reliable supplies of a wide range of expensive second-line age nts would have to be supplied; operational studies would be required to det ermine the indications for and format of the expanded programmes; financial and technical support from international organizations and Western governm ents would be needed in addition to that obtained from local governments.