Demonstration of Mycobacterium kansasii species heterogeneity by the amplification of the 16S-23S spacer region.

Amplification of the region separating the genes coding for the two rRNA species 16S and 23S was performed with 56 strains of several mycobacterial species, including 21 clinical isolates of Mycobacterium kansasii and the M. kansasii type strain ATCC 12478. On the basis of PCR product profiles, the previously suggested heterogeneity of M. kansasii species was confirmed. Three subgroups were identified; members of the first subgroup showed the same PCR profile as the reference strain. Different profiles were obtained for the two other subgroups. Amplification of the 16S-23S spacer is rapid and simple and, consequently, may be a helpful tool for identification and characterisation of M. kansasii isolates in epidemiological analysis.