[Detection of Mycobacterium intracellulare by PCR]

PCR products amplified with the primers YNP-1 and YNP-2 and template DNA from various mycobacterial species showed differences in molecular sizes. By sequencing the PCR products, we found that the DNA fragment from M. tuberculosis and that of M. intracellulare have different DNA sequences. The former was 164 bp, composed of 27 A, 54 C, 57 G, and 26 T, while the latter was 109 bp, composed of 22 A, 37 C, 34 G, and 16 T. We compared these sequences and selected a nucleotide sequence unique to M. intracellulare and used as primer YNP-7. Antisense primer, YNP-8, was constructed from the complementary sequence of YNP-2 which is located about 270 b downstream of YNP-7. Results of PCR using the primers YNP-7 and YNP-8 and template DNA of various mycobacteria showed that positive results were only with the template DNA from M. intracellulare. Bacterial DNA from those other than mycobacteria but appear in sputum were tested in PCR with the primers YNP-7 and YNP-8. None of them showed positive results. Specificity of the PCR products was determined with a specific probe MIP which was constructed using a sequence between YNP-7 and YNP-8 to confirm the specificity of PCR by Southern hybridization. Only the products from M. intracellulare hybridized with the probe MIP, indicating the specificity of YNP-7 and YNP-8 to M. intracellulare.(ABSTRACT TRUNCATED AT 250 WORDS)