Drug-resistant TB (DR-TB) is a growing worldwide problem, with no country or region spared.
Multidrug-resistant TB (MDR-TB) is defined as TB that is resistant to at least isoniazid and rifampicin.
Extensively drug-resistant TB (XDR-TB) is defined as TB that is resistant to isoniazid and rifampin, any fluoroquinolone and at least one of three injectable second-line drugs (amikacin, kanamycin or capreomycin).
In 2008, an estimated 390,000 to 510,000 MDR-TB cases emerged globally (best point estimate is 440,000 cases)7. Among incident TB cases globally, 3.7% of new cases and 20% of previously treated cases are estimated to have (MDR-TB)19. In 2008, MDR-TB caused an estimated 150,000 deaths.
In some parts of the world, like the former Soviet Union and Eastern Europe, the percent of new and previously treated TB cases with DR-TB is alarmingly high with some areas reporting greater than 30% in new cases and greater than 70% in retreatment cases (e.g. Belarus).
In contrast, in countries like China and India, the percentage of new cases with MDR-TB is low, but due to the high TB incidence and population density, these countries yield a disturbingly high estimate of absolute number of MDR-TB cases. It is estimated that almost 50% of the world’s cases of MDR-TB occur in China and India alone.
Africa does not have survey data for DR-TB for all countries. However the limited survey data in the continent suggests that the MDR-TB burden is significant in some regions, especially in Southern Africa.
As of 2012, XDR-TB, has been identified in 84 countries, such that the average proportion of MDR-TB cases with XDR-TB is estimated to be 9%19.