Rapid and efficient detection of Mycobacterium tuberculosis in respiratory and non-respiratory samples

The detection of Mycobacterium tuberculosis using a new commercial real-time polymerase chain reaction (PCR) assay (Xpert (TM) MTB/RIF) was evaluated on 91 respiratory and 89 non-respiratory samples recovered from 132 patients suspected of tuberculosis (TB). Overall, 31 (17.2%) of the 180 samples, including 17 respiratory and 14 non-respiratory (respectively 17 and 12 PCR-positive), yielded M. tuberculosis on culture. The sensitivity and specificity of PCR were respectively 100% and 100%, and 85.7% and 97.3% for respiratory and non-respiratory samples. Although the test is validated only for respiratory samples, our findings suggest that it could be useful for the diagnosis of extra-pulmonary TB.