Limited variation of DNA fingerprints (IS6110 and IS1081) in Korean strains of Mycobacterium tuberculosis

Abstract

Objective: To establish the usefulness of DNA fingerprinting for the epidemiology of Mycobacterium tuberculosis isolated from Korean tuberculosis patients.

Methods: Comparison of restriction fragment length polymorphism (RFLP) patterns produced by southern hybridization of PvuII-digested chromosomal DNA.

Results: IS6110-associated banding patterns of 41 isolates varied considerably, containing 1-13 copies. The RFLP pattern of the epidemiologically related M. tuberculosis isolates was identical in 8 of 10 groups of close contact patients. No noticeable differences in RFLP were observed between drug-sensitive and drug-resistant isolates. IS1081-containing restriction fragment analysis of 52 isolates showed 6 different banding patterns, and the C type was found dominant in Korea. Identification of G type M. tuberculosis, which has a 8.0 kb IS1081-containing PvuII fragment, is unusual because it has been observed only in M. bovis BCG so far.

Conclusions: IS6110 was a very useful tool for tracing the transmission route of tuberculosis; IS1081 was also useful for subdividing M. tuberculosis into several groups.