MULTIPLE-DRUG RESISTANCE - A WORLD-WIDE THREAT

The emergence of drug-resistant Mycobacterium tuberculosis threatens t he ability of existing health care programmes to treat tuberculosis ef fectively. Mycobacterium tuberculosis becomes drug resistant primarily through mutations within antituberculosis drug target genes; patient non-compliance with anti-tuberculosis therapy and/or inadequate drug l evels promote the selection of these mutations. Drug-resistant tubercu losis can also occur via transmission of an already drug-resistant str ain to a susceptible individual. Molecular epidemiology, together with drug sensitivity testing, has shown that transmission accounts for >5 0% of the incidence of drug-resistant disease. This demonstrates the i nability of current programmes to contain the spread of resistance. Th e success of future tuberculosis control will depend on a global commi tment to directly observed therapy and further research into epidemiol ogy, modem diagnostics and new treatments.