Abstract: Objective To develop a rapid method with high sensitivity and specificity to detect 4 mycobacterial species(M. tuberculosis, M. avium, M. intracellulare and M. kansasii) which are the most common opportunistic Mycobacteria in AIDS patients. Methods The sensitivities and specificities of PCR were determined with different primer pairs targeting various mycobacterial genes. Multiplex PCR with combination of 4 primer pairs was used to detect the template mixtures of either 1, 2 or 3 mycobacterial DNA. Sensitivities of multiplex PCR were measured. Results Specific DNA fragments of 4 mycobacterial species mentioned above could be detected by PCR and sensitivities ranged from 1×10¹~1×10² cells/mL, while the other 17 mycobacterial strains were all PCR-negative. Multiplex PCR could amplify the corresponding 1, 2 or 3 DNA fragments, depending on the number of template DNA added, and sensitivities of multiplex PCR ranged from 1×10²~1×10³ cells/mL. Conclusions Multiplex PCR is a rapid, sensitive and specific method for differentiation and detection of Mycobacteria.

Key words: Mycobacterium avium, Mycobacterium avium complex, Mycobacterium kansasii, Polymerase chain reaction, Mycobacterium tuberculosis