The sequence analyses of 16S rRNA genes of mycobacteria

To establish the sequence analysis of 16S rDNA of mycobacteria for the identification of mycobacterial strains isolated from patients.The 5' end fragments (～500bp) of 16S rRNA genes were amplified from 29 mycobacterial strains isolated from sputa of the patients with lung infection in a hospital of Chongqing city by polymerase chain reaction (PCR) and the DNA fragments were directly sequenced. The sequences obtained in this study were compared with the 16S rDNA sequneces reported in GenBank by software of DNA analyses. Results showed the 16S rDNA sequences from 14 strains were identical to that of MTC, M.gordonae, M.neoaurum, M.chlorophenolicum, and M.abscessus/ M.chelonae. Therefore, these strains may correctly be identified based on the identical sequences. Some of the 16S rDNA sequences of the isolated strains were not identical to any sequence in the GenBank,but similar to sequences of certain mycobacterial species. The sequence comparison of 16S rDNA sequences between the isolates and the members of mycobacterial genus revealed that certain strains isolated in Chongqing are the new species or subspecies. It is concluded that 16S rDNA sequence analyses may be a reliable, rapid, and low costs way for identification of mycobacterial strains and the species of mycobacteria causing lung infection in Chongqing are different from that reported previously.