Multiplex polymerase chain reaction for rapid detection of atypical mycobacteria and Mycobacterium tuberculosis complex.

A three-step polymerase chain reaction (PCR) method was developed for the detection and typing of mycobacterial DNA in clinical samples and fixed tissue specimens. The first step was to rule out or prove the presence of DNA of Mycobacterium tuberculosis complex. An amplified fragment from the insertion sequence (IS) 6110 was used for this purpose. Patients negative for IS 6110 were evaluated for a fragment of the 65 kDa-antigen, present in all mycobacteria. In positive patients, a multiplex PCR was performed for M. gordonae, M. avium, M. kansasii, M. fortuitum, and M. malmoense, combined in one PCR run. As another control, to prove mycobacterial DNA, PCR was used for the gene coding for the 16S ribosomal RNA also found in all mycobacteria. Appropriate negative controls were included. Different clinical samples were compared for an efficient amplification of these different mycobacterial DNA fragments. Different mycobacteria can be identified within one day in either unfixed cytologic and bacteriologic samples, or formalin-fixed paraffin-embedded tissue samples. Therefore, this method is a quick, cost efficient, and reliable tool to identify mycobacteria other than the tuberculosis complex.