Abstract: Objective To establish and evaluate a multiplex PCR technique to rapid differentiate Mycobacterium tuberculosis complex (MTBC) from non-tuberculous mycobacteria (NTM). Methods Three pairs of oligo nucleotide primers were used in the multiplex PCR reaction. A 473 bp DNA fragment encoding oxyR-ahpC intergenic region in MTBC, a 235 bp and 136 bp DNA fragment encoding variable rpoB gene region from MTBC and NTM, respectively, were amplified. The multiplex PCR was assessed in 6 reference strains of MTBC, 50 reference strains of NTM, 312 clinical strains of MTBC and 300 clinical strains of NTM. Results The multiplex PCR produced two DNA fragments at the size 473 bp and 235 bp for MTBC reference strains, and one DNA fragment with the size 136 bp for NTM reference strains. Among 312 MTBC clinical samples, the sensitivity was 99.36% (310/312) and specificity was 99.32% (294/296). Among 300 NTM clinical samples, the sensitivity and specificity were 98.00% (294/300) and 100.00% (310/310) respectively. Conclusion The multiplex PCR can differentiate MTBC and NTM efficiently, and might be a valuable technique for clinical use.

Key words: Mycobacterium tuberculosis, Mycobacterium, Multiplex polymerase chain reaction