[Comparison on discriminatory power of different variable number tandem repeats locus-set on genotyping of mycobacterium tuberculosis isolated in China].
OBJECTIVE
To evaluate the application of different variable number tandem repeats (VNTR) locus in genotyping of Mycobacterium tuberculosis (M.tuberculosis) strains isolated from eight provinces in China, and to find the suitable locus-set of VNTR for epidemical strains in China.


METHODS
All 140 M.tuberculosis strains were randomly selected from 2800 M.tuberculosis strains isolated from eight provinces in China, 27 VNTR loci were used for typing all isolates. Discriminatory power (Hunter-Gaston Index, HGI) of every locus and different locus-set were analyzed by BioNumerics software. Meanwhile, Spoligotyping was used to identify Beijing family and non-Beijing family. Then the HGI of different locus-sets in two families was also evaluated.


RESULTS
All 140 isolates were clustered into Beijing kindred (112 strains, 80%) and non-Beijing kindred (28 strains, 20%) by Spoligotyping. The discriminatory power of Spoligotyping in 140 isolates was 0.4589. Every locus showed different polymorphism and HGI were from 0 to 0.809. The number of VNTR loci with HGI higher than 0.5 in all strains, Beijing family and non-Beijing family was 8, 7 and 14 respectively. 27 loci were combined into four groups which included 8, 12, 15 and 24 VNTR loci respectively. Four locus-sets showed different polymorphism, HGI of eight-locus, 12-locus, 15-locus, and 24-locus set in 140 strains was 0.9991, 0.9882, 0.9980 and 0.9986, and their discriminatory power were calculated in Beijing kindred (HGI: 0.9987, 0.9318, 0.9969 and 0.9975) and non-Beijing kindred (HGI: 1, 0.9894, 1 and 1).


CONCLUSIONS
Different VNTR locus and locus-set showed different discriminatory power in the selected M.tuberculosis strains isolated from China. Eight-locus set can be used in molecular epidemiological study of M.tuberculosis in China after standardization.
Li
Zhao-na
ZN
Beijing Children's Hospital Affiliated to Capital Medical University, Beijing, China.
Liu
Mei
M
Lü
Bing
B
Zhao
Xiu-qin
XQ
Liu
Zhi-guang
ZG
Jiao
Wei-wei
WW
Sun
Lin
L
Jia
Wen-xiang
WX
Shen
A-dong
AD
Wan
Kang-lin
KL
D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D020080:Tandem Repeat Sequences
D004269:DNA, Bacterial