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Open Access Highly Accessed Research article

Genetic diversity of Mycobacterium tuberculosis isolates from Beijing, China assessed by Spoligotyping, LSPs and VNTR profiles

Bing Lu1, Ping Zhao2, Binbin Liu13, Haiyan Dong1, Qin Yu14, Xiuqin Zhao1 and Kanglin Wan1*

Author Affiliations

1 State Key Laboratory for Infectious Diseases Prevention and Control, National Institute for Communicable Disease Control and Prevention & National Tuberculosis Reference Laboratory, Chinese Center for Disease Control and Prevention, Beijing 102206, P. R. China

2 Chaoyang Centre for Disease Control and Prevention, Beijing, 100021, P. R. China

3 Hunan Provincial Institute for Tuberculosis Prevention and Control, Changsha, 410006, P. R. China

4 University of South China, Hengyang, 421001, P. R. China

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BMC Infectious Diseases 2012, 12:372  doi:10.1186/1471-2334-12-372

Published: 23 December 2012

Abstract

Background

Tuberculosis is one of the most infectious diseases in the world. Molecular typing methods such as spoligotyping, and VNTR (variable number tandem repeats), IS6110 in the NTF region and LSP (large sequence polymorphisms) analysis are generally useful tools for the resolution of various issues related to the classical epidemiology of Mycobacterium tuberculosis (M. tuberculosis).

Methods

To determine the transmission characteristics of M. tuberculosis strains isolated in Beijing, China, and their genetic relationships, especially those among Beijing family strains, 260‚ÄČM. tuberculosis strains isolated from patients presenting pulmonary tuberculosis were analyzed by spoligotyping, and by examining 22 VNTR loci and the presence/absence of IS6110 in the NTF region, RD105 and RD181.

Results

81% (211 strains) of the isolates studied were Beijing family strains, 174 (82.5%) of which were identified as modern Beijing strains based on the presence of IS6110 upstream of the NTF region. RD181 was intact in 9 of the other 37 (17.5%) ancestral Beijing strains. The percentage of Beijing family strains in this study was consistent with previous reports. There are many differences, however, in allele diversity among VNTR loci between reports on strains from different areas.

Conclusions

The Beijing family is the most prevalent genotype in Beijing city and the predominance of Beijing family strains has not altered in almost twenty years. Differences in the alleles and discrimination ability of VNTR loci between different regions is likely due to population differences in the regions where these M. tuberculosis strains were isolated or to differences in sampling times.

Keywords:
M. tuberculosis; Beijing family; Genotyping