[IS6110 restriction fragment length polymorphism analysis of Mycobacterium tuberculosis isolated in Okayama Prefecture].

Similarity of restriction fragment length polymorphism (RFLP) patterns of Mycobacterium tuberculosis isolated in Okayama Prefecture from December 1999 to December 2001 was investigated. The RFLP patterns showed diversity, 342 different RFLP patterns were found among 395 strains. There were 34 identical clusters (84 strains). The source of infection in the identical clusters was the same in 20 percent, however, in patients younger than 60 years old, the identical rate was 60 percent. These results suggest that, in comparatively younger patients, the identical RFLP pattern is an important index. In general, 40 percent strains including organized 4 main prevalent strains showed similar patterns. Because the patterns shown in these prevalent strains agreed with the patterns often found in the strains from patients in the other areas of Japan, it was revealed that they were endemic strains not only in Okayama Prefecture but also in many areas of Japan.