Reproducibility of 15-Loci MIRU-VNTR Method in Mycobacterium tuberculosis Genotyping

Mycobacterium tuberculosis genotyping is an essential step for understanding the epidemiology of tuberculosis. Mycobacterial-interspersed-repetitive-units (MIRU)-variable-number-of-tandem-repeats (VNTR) typing is an important method for this purpose. The study aimed to determine the reproducibility of 15-loci MIRU-VNTR method. DNA extraction and 15-loci MIRU-VNTR were carried out for genotyping of 60 M. tuberculosis isolates collected from different clinical samples of 27 M. tuberculosis patients, each with two to four clinical isolates of M. tuberculosis. The similarity of M. tuberculosis isolates of the same patient was investigated by MIRU-VNTRplus. The patterns of MIRU-VNTR were identical in 43 M. tuberculosis isolates collected from 20 tuberculosis patients, giving the repeatability of 71.6% for the test. In 12 isolates of M. tuberculosis belonging to five patients, the variable-number tandem repeat (VNTR) in only one locus was different. In three M. tuberculosis isolates of one patient, two different genotypes were identified. This study confirms the high reproducibility of 15-loci MIRU-VNTR, except for limited cases.