Molecular genotyping of Mycobacterium tuberculosis in Xi'an, China, using MIRU-VNTR typing

作者:Zhou, A.; Nawaz, M.; Xue, X.; Karakousis, P. C.; Yao, Y.; Xu, J.*
来源:International Journal of Tuberculosis and Lung Disease, 2011, 15(4): 517-522.
DOI:10.5588/ijtld.10.0495

摘要

SETTING: The molecular genotyping of Mycobacterium tuberculosis is expected to lead to a better understanding of M. tuberculosis transmission in Xi'an, one of the largest cities in Western China. OBJECTIVE: To characterize the population of M. tuberculosis strains circulating in Xi'an and to evaluate the feasibility of the mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing method. DESIGN: A total of 195 M. tuberculosis clinical isolates from Xi'an were genotyped using spoligotyping and MIRU-VNTR. RESULTS: Thirty-two different genotypes were identified by spoligotyping, with the Beijing family identified as the largest lineage (84.6%), followed by the T1 (3.08%), T2 (1.54%), H3 (1.03%) and U (1.03%) families. The Hunter-Gaston discriminatory index (HGDI) of spoligotyping is low (HGDI = 0.392). In contrast, 15-locus MIRU-VNTR shows a higher discriminatory power (HGDI = 0.998) than 12-locus MIRU-VNTR (HGDI = 0.948). By replacing the ETR C locus with the MIRU39 locus, the discriminatory power of 15-locus MIRU-VNTR is increased to 0.999. CONCLUSIONS: The Beijing family accounts for the vast majority of M. tuberculosis isolates in Xi'an, China. The modified 15-locus MIRU-VNTR showed high HGDI and can be used as a first-line genotyping method in combination with spoligotyping in routine epidemiological investigations in Xi'an, China.