Genotype analysis of 211 mycobacterium tuberculosis clinical isolates from southern China by 48-locus MIRU-VNTR

Abstract

Objective To explore a suitable MIRU-VNTR technique for analyzing the genotype of mycobacterium tuberculosi (TB) clinical isolates from southern China. Methods 211 isolates were resuscitated and cultured in 7H10 medium. After the DNA was extracted, all the clinical isolates were genotyped by 48-locus MIRU-VNTR with Polymerase Chain Reaction (PCR),in which the 48 locus VNTR were included, and the Hunter Gaston Discriminatory Index(HGDI) was calculated. On the basis that the VNTR locus of which HGDI was larger than 0.6 has higher resolution, the combination of the locus with higher resolution for the genotyping of mycobacterium tuberculosis in southern China were determined. Results Finally we found 30 of the 48 locus VNTR could be amplified steadily, and its’ HGDI values were between 0.09 and 0.87. The HGDI of 16 VNTR locus, including VNTR 3192, VNTR 2996, VNTR 2461, VNTR 4052, VNTR 4155, VNTR 1895, VNTR 1955, VNTR 0960, VNTR 4348, VNTR 0595, VNTR 1305, VNTR 0154, VNTR 2687, VNTR 2401, VNTR 2347, and VNTR 1907, were all larger than 0.6, and the total HGDI under the combination of these 16 loci was greater than 0.98. Conclusion The 16 loci mentioned above should be adopted in the relevant research, in which MIRU-VNTR technique will be carried out to analyze the genotype of mycobacterium tuberculosis in southern China. Key words: Mycobacterium tuberculosis; MIRU-VNTR; HGDI; genotyping