Detection of Mycobacterium tuberculosis Complex and Differentiation of Five Common Nontuberculous Mycobacteria Directly from Clinical Specimens Using a Multiplex PCR Assay.

Rapid detection and differentiation of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM) are crucial for appropriate treatment selection. The NeoPlex™ TB/NTM Detection Kit is a PCR assay that simultaneously detects MTBC and NTM and identifies five clinically important NTM species (M. intracellulare, M. avium, M. kansasii, M. abscessus subsp. abscessus, and M. abscessus subsp. massiliense). We evaluated its comparative analytical performance using 200 stored nucleic acid extracts from respiratory and non-respiratory MTBC- or NTM-positive clinical specimens after excluding 27 specimens without interpretable species-level results. Results were compared with those of a line probe assay (LPA), which formed the reference test. Concordance with the LPA was 93.0%, including 96.9% for MTBC and 92.3% for NTM. The NeoPlex assay correctly differentiated all MTBC- and NTM-positive specimens included in the study cohort. For species-level identification, sensitivity and specificity were 98.9% and 100% for M. intracellulare, 97.6% and 100% for M. avium, 82.4% and 100% for M. kansasii, 79.0% and 100% for M. abscessus subsp. abscessus, and 100% and 100% for M. abscessus subsp. massiliense, respectively. These findings suggest that this multiplex PCR assay enables rapid, accurate detection and differentiation of MTBC and NTM species directly from clinical samples.