Tuberculosis remains a major public health concern. Existing diagnostic tools are slow and result in delays initiating appropriate treatment. This is particularly a problem in patients with HIV, in whom sputum–smear analysis is frequently negative and those with multi-drug resistant strains.
In this study, the performance of an automated molecular assay for Mycobacterium tuberculosis (MTB) and resistance to rifampin (RIF) (Xpert MTB/RIF) was assessed. This test, through detection of an MTB-specific sequence of the rpoB gene and probing for rifampin-resistance determining region mutations, provides results within 2 h.
Three sputum samples were analysed from 1730 eligible patients with suspected tuberculosis in reference laboratories in Peru, Azerbaijan, South Africa and India. With a single test, 98.2% of patients with smear-positive, culture-positive tuberculosis were identified. Among those with smear-negative, culture-positive disease, the sensitivity of the assay was 72.5% with one test, 85.1% for two tests and 90.2% for three tests. The...