[Molecular epidemiological analysis of Mycobacterium kansasii isolates]

To make molecular epidemiological analysis of Mycobacterium kansasii (M. kansasii) isolates.

We examined 174 M. kansasii isolates from clinical samples of patients at National Hospital Organization Kinki-chuo Chest Medical Center from June 1, 2002 to August 31, 2005 by polymerase chain reaction (PCR) -restriction analysis (PRA) of the heat shock protein (hsp) 65 gene (hsp65-PRA), sequencing (ITS, 16S-23S internal transcribed spacer, and hsp65 for discrepant case between hsp65-PRA and ITS sequence), pulsed-field gel electrophoresis (PFGE), and restriction fragment length polymorphism (RFLP) with the major polymorphic tandem repeat (MPTR) probe and the IS1652 probe of genomic DNA.

Of the 174 M. kansasii isolates, 170 strains were classified as M. kansasii type I using hsp65-PRA, while two isolates belonged to type II and one each isolate to type IIb and VI, respectively. Although the ITS sequence of these isolates also identified the same region of polymorphism by hsp 65-PRA, only type II b might be revealed atypical type II, a transitional type from typical type II to intermediate type I by hsp65 sequence. The polymorphic patterns by RFLPs with MPTR and IS1652 probe were shown specific for each homogeneous cluster by hsp 65-PRA. In addition, 159 isolates were recognized the same common pattern A by PFGE analysis. In contrast, the rest 15 isolates revealed significant polymorphism within 11 isolates of type I, and 4 isolates among type II, IIb, and VI.

We verified the M. kansasii genotype I was predominant, with the same pattern of major worldwide type regions, and reflected a very tight clonal structure. Type I was furthermore indicated recognition of subtypes by PFGE analysis.