Rapid drug resistance detection in Mycobacterium tuberculosis: a review of colourimetric methods

Several new methods to detect drug resistance in Mycobacterium tuberculosis have been proposed in recent years. Colourimetric methods that use redox indicators or the nitrate reduction assay have received increasing attention because of their simplicity and the absence of any requirement for sophisticated equipment or highly trained personnel. Several studies have evaluated their accuracy and performance in comparison with reference standard methods, particularly for the detection of resistance to rifampicin and isoniazid, which are the two most important drugs used for the treatment of tuberculosis. This review describes the development, evaluation and implementation of these methods as rapid alternative tests for the detection of multidrug resistance in M. tuberculosis. Based on published evidence and the high accuracy of colourimetric methods for detecting drug resistance in M. tuberculosis, these methods seem to be appropriate for implementation in high-burden low-resource countries.