Tuberculosis in the developing world: recent advances in diagnosis with special consideration of extensively...

Globally tuberculosis is mainly diagnosed by sputum smear microscopy, which fails to detect half of all cases and fails to identify drug resistance. Inadequate global tuberculosis control through the directly observed therapy short course strategy alone and the growing threat of multidrug-resistant and extensively drug-resistant tuberculosis has driven recent development of new commercial and noncommercial tests, which are most desperately needed in resource-limited, high-burden settings. This review outlines the range of options currently available, highlighting particularly those recent developments with greatest potential for addressing the growing multidrug-resistant and extensively drug-resistant disaster as it affects those communities least technically and financially capable of controlling it.

Simplification of molecular-diagnostic techniques, rapid-liquid culture and the use of colorimetric indicators have improved the sensitivity, speed and reliability of tuberculosis and multidrug-resistant tuberculosis detection, while decreasing cost and bringing diagnosis closer towards (though still some way from) the point-of-care.

Global tuberculosis control in 2008 demands the use of new tools for more sensitive and rapid detection of active disease and of drug resistance. Improved technologies are available for reference laboratories but for settings where resources and technical capacity are limited there is little ready for field implementation. The pipeline is promising, but in the interim wider use of liquid culture and manual or colorimetric drug susceptibility testing should be promoted.