Characteristics of Molecular Strain Typing of Mycobacterium tuberculosis Isolated from Korea.

Molecular strain typing of Mycobacterium tuberculosis is important for the detection of outbreaks of tuberculosis and laboratory cross contamination, as well as the differentiation between re-infection and reactivation of tuberculosis. In the present review, the authors investigated the currently available typing methods for M. tuberculosis and the current status of strain distribution in Korea. IS6110-restriction fragment length polymorphism (RFLP), which is considered a standard method, is based on numbers and positions of the insertion sequence, IS6110. The method has an excellent discriminatory power with a considerable amount of worldwide data, although it is time-consuming and labor-intensive. Spoligotyping is based on the presence or absence of spacer sequences between direct repeat (DR) regions. PCR amplification allows for the possibility of application in the early suspicious stage. The data can be easily digitized; however, it shows identical profiles in Beijing family strains. Mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRUVNTR) is another PCR-based genotyping method with a good discrimination power whose data can also be easily digitized. In Korea, the prevalence of Beijing family strains have been as high as 80 to 87%. (Korean J Clin Microbiol 2011;14:41-47)