• 대한의생명과학회지
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• 제26권3호
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• pp.170-178
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• 2020

Mycobacterium tuberculosis (MTB) continues to be one of the main causative agents of tuberculosis (TB); moreover, the incidence of nontuberculous mycobacteria (NTM) infections has been rising gradually in both immunocompromised and immunocompetent patients. Precise and rapid detection and identification of MTB and NTM in respiratory specimens are thus important for MTB infection control. Molecular diagnostic methods based on the nucleic acid amplification test (NAAT) are known to be rapid, sensitive, and specific compared to the conventional acid-fast bacilli (AFB) smear and mycobacterial culture methods. In the present study, the clinical performances of three commercial molecular diagnostic assays, namely TB/NTM PCR (Biocore), MolecuTech Real MTB-ID^® (YD Diagnostics), and REBA Myco-ID^® (YD Diagnostics), were evaluated with a total of 92 respiratory specimens (22 AFB smear positives and 67 AFB smear negatives). The sensitivity and specificity of TB/NTM PCR were 100% and 75.81%, respectively. The corresponding values of MolecuTech Real MTB-ID^® and REBA Myco-ID^® were 56.52% and 90.32%, and 56.52% and 82.26%, respectively. TB/NTM PCR showed the highest sensitivity; however, the concordant rate was 10% compared with sequence analysis. Although MolecuTech Real MTB-ID^® showed lower sensitivity, its specificity was the highest among the three methods. REBA Myco-ID^® allowed accurate classification of NTM species; therefore, it was the most specific diagnostic method. Of the three PCR-based methods, MolecuTech Real MTB-ID^® showed the best performance. This method is expected to enable rapid and accurate identification of MTB and NTM.

• 대한의생명과학회지
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• 제25권4호
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• pp.426-430
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• 2019

Currently, molecular diagnostic assays based on nucleic acid amplification tests have been shown to effectively detect mycobacterial infections in various types of specimen, however, variable sensitivity was shown in FFPE samples according to the kind of commercial kit used. The present study therefore used automated PCR-reverse blot hybridization assay (REBA) system, REBA Myco-ID HybREAD 480^®, for the rapid identification of Mycobacterium species in various types of human tissue and compared the conventional one-tube nested-PCR assay for detecting Mycobacterium tuberculosis (MTB). In conventional nested-PCR tests, 25 samples (48%) were MTB positive and 27 samples (52%) were negative. In contrast, when conducted PCR-REBA assay, 11 samples (21%) were MTB positive, 20 samples (39%) were NTM positive, 8 samples (15%) were MTB-NTM double positive, and 13 samples (25%) were negative. To determine the accuracy and reliability of the two molecular diagnostic tests, the one-tube nested-PCR and PCR-REBA assays, were compared with histopathological diagnosis in discordant samples. When conducted nested-PCR assay, 10 samples (59%) were MTB positive and seven samples (41%) were negative. In contrast, when conducted PCR-REBA test, three samples (17%) were MTB positive, 10 samples (59%) were NTM positive and four samples (24%) were negative. In conclusion, the automated PCR-REBA system proved useful to identify Mycobacterium species more rapidly and with higher sensitivity and specificity than the conventional molecular assay, one-tube nested-PCR; it might therefore be the most suitable tool for identifying Mycobacterium species in various types of human tissue for precise and accurate diagnosis of mycobacterial infection.