Detection of Mycobacterium tuberculosis complex Using Real-time Polymerase Chain Reaction

Abstract

Background : For the detection of Mycobacterium tuberculosis complex (MTB), PCR is known to be sensitive, specific, and rapid compared to the conventional methods of acid-fast-bacilli (AFB) smear and culture. We evaluated a new approach for MTB detection using real-time PCR.Methods : The specificity of real-time PCR was evaluated using 20 MTB isolates and 37 nontuberculous mycobacteria (NTM) isolates identified by AccuProbe Mycobacterium tuberculosis complex colony identification test (Gen-Probe Inc., USA) and Myco-ID (M&D, Korea). One hundred sputum specimens (50 AFB smear-positive and 50 negative specimens) were analyzed using real-time PCR and Amplicor Mycobacterium tuberculosis test (Roche, Germany). The results of real-time PCR positives (55 samples) and negatives (598 samples) were analyzed by AFB smear and culture.Results : The real-time PCR assay accurately discriminated between MTB and NTM species. Realtime PCR and Amplicor test yielded the same results in 96.0% (96/100) of the sputum specimens tested. The sensitivity and specificity of real-time PCR based on AFB culture were 97.4% and 88.5%, respectively. Of the 55 real-time PCR positive specimens, 83.6% (46/55) were culture-positive, 30.9 % (17/55) were smear-positive, 52.7% (29/55) were smear-negative and culture-positive, and 14.5% (8/55) were both smear and culture-negative. Among the 598 real-time PCR negative specimens, 60 were not tested for AFB smear or culture and 10 were contaminated. Of the remaining 528 specimens, 478 (90.5%) were both smear and culture-negative and 39 (7.4%) were culture-positive.Conclusions : For the detection of MTB, real-time PCR was sensitive and specific and comparable to conventional methods. It can be used for rapid identification of M. tuberculosis in clinical laboratories. (Korean J Lab Med 2008;28:103-8)

Comparison of Diagnostic Performance of Three Real-Time PCR Kits for DetectingMycobacteriumSpecies

“…In addition, the need to differentiate MTB and NTM is gaining more importance, owing to the growing occurrence of NTMs and the fact that both MTB and NTM require different medications 2. In the present study, therefore, we compared and assessed the diagnostic performance of three types of commercial real-time PCR kits for MTB detection and NTM differentiation, as well as two PCR methods previously implemented in our hospital.…”

“…According to a recent WHO report, 1.6 million people worldwide died of TB in 2005 1. Korea has shown a higher prevalence of mycobacterial infection than most of the other developed countries, and the prevalence of non-tuberculous mycobacterium (NTM) infection has increased in the developed countries 2. Therefore, an increased emphasis has currently been placed on the rapid identification of Mycobacterium tuberculosis (MTB) and NTM 2,3…”

Evaluation of Propidium Monoazide Real-Time PCR for Early Detection of Viable Mycobacterium tuberculosis in Clinical Respiratory Specimens

“…To improve its sensitivity and specificity, various molecular methods based on nucleic acid amplification have been developed and applied in clinical laboratories [3, 4]. However, none of these approaches can discriminate between viable and dead cells because bacterial DNA (the target of the test) is present in both cases.…”

The Combination of Real-Time PCR and HPLC for the Identification of Non-Tuberculous Mycobacteria

“…The AdvanSure real-time PCR assay has an overall sensitivity of 66.7-100%. Specifically, 86.8-100% specificity was obtained using AFB smear-positive specimens [6, 14, 15], and 55.6-75% sensitivity in NTM isolation assays [6, 15]. In our study, the real-time PCR assay showed 45.1% sensitivity (95% confidence interval, 36.5-53.9%) among the clinical specimens determined to be NTM-culture-positive.…”