[Automated RNA amplification for the rapid identification of Mycobacterium tuberculosis complex in respiratory specimens]

Multicenter evaluation of a transcription-reverse transcription concerted assay for rapid detection of mycobacterium tuberculosis complex in clinical specimens

A European multicenter study was performed to evaluate the performance of a new method, based on the transcription-reverse transcription concerted reaction (TRC-2), which enabled one-step amplification and real-time detection of the Mycobacterium tuberculosis 16S rRNA target directly in clinical specimens. A total of 633 respiratory and nonrespiratory specimens were tested, and the results were compared with those from smears and cultures. A total of 129 patients (Paris center) were followed up in order to evaluate the clinical performance of TRC-2. By using M. tuberculosis complex strains to inoculate sterile sputa, the detection limit of TRC-2 was found to be 30 to 50 CFU/ml. A total of 548 respiratory specimens and 59 extrapulmonary specimens were assessable. For pulmonary specimens, the sensitivities of TRC-2 and acid-fast smear were 86.8% and 50.4%, respectively (P = 0.002). The specificities were 97.5% and 100%, respectively. For extrapulmonary specimens, the sensitivities of TRC-2 and acid-fast smear were 83.3% and 8.3% (P < 0.0001), and the specificities were 95.8% and 100%, respectively. Fifteen of 129 patients were diagnosed with pulmonary tuberculosis (TB). The sensitivities of culture and TRC-2 were 80% (12/15) and 86.7% (13/15) (P = 0.16), and the specificities were 100% and 93.9%, respectively. Based on an 11.6% incidence of TB in our population, the positive predictive values of TRC-2 and culture were 81.3% and 100%, respectively, and the negative predictive values were 98.2% and 97.4%, respectively. These results demonstrated that detection of M. tuberculosis complex in clinical specimens by TRC-2 with ready-to-use reagents was an efficient and rapid method for the diagnosis of pulmonary and extrapulmonary TB.