Restriction fragment length polymorphism analysis of Mycobacterium tuberculosis isolated from countries in the Western Pacific Region

A total of 422 Mycobacterium tuberculosis isolates from eight countries wer e subjected to IS6110 and IS1081 DNA fingerprinting by means of restriction fragment analysis to characterize ICL tuberculosis strains from each count ry. Chinese, Mongolian, Hong Kong, Filipino, and Korean isolates had compar atively more copies of IS6110 (proportion with eight or more copies; 95% +/ - 5%), while Thai, Malaysian, and Vietnamese isolates had fewer copies (pro portion with eight or more copies, 60% +/- 4%). We found a number of novel IS1081 types in this study, One IS1081 type was present in 56% of Filipino isolates, had a specific 6.6-kb PvuII fragment in its IS6110 DNA fingerprin t, and was termed the "Filipino family." The IS1081 types of Thai isolates had interposing characteristics between the characteristics of northeastern Asian and southeastern Asian IS1081 types. A 1.3-kb single-copy IS6110 fra gment was found only in Vietnamese M. tuberculosis isolates. Although M. tu berculosis isolates from each country had comparatively similar characteris tics depending on the classification factor, each country's isolates showed characteristic DNA fingerprints and differed slightly from the isolates fr om the other countries in either the mode number of IS6110 copies or the di stribution of IS1081 types.