We evaluate the performance of Xpert MTB/RIF for the diagnosis of extrapulmonary tuberculosis （EPTB） in China. The performance of Xpert was evaluated compared to the composite reference standard （CRS）, drug susceptibility testing （DST）, and imaging examination. The overall sensitivity and specificity of Xpert were 64.1% （195/304） and 100% （24/24）, respectively, using CRS as the gold standard. The sensitivity was significantly higher than that of culture for pus （P〈0.05）. The proportion of EPTB-positive cases diagnosed by imaging was two times more than that diagnosed using Xpert; however, 6 out of 19 cases may have been overdiagnosed by imaging.
YUAN MeiLYU YanCHEN Su TingCAi ChaoLI YuanZHANG Zhi GuoLI Yun XuDONG Ling LingFU Yu HongHUANG Hai RongGAO Ji MinLI Wei Min
Our study was to investigate the epidemiological characteristics of M.tuberculosis from a national tuberculosis referral center in China. All strains isolated from TB patients, were genotyped by the RD105 deletion, 8 and 51 SNP loci and VNTR. The high differentiation SNPs of modern Beijing strains were analyzed for protein function and structure. 413 M. tuberculosis were included. Of 379 Beijing lineage M. tuberculosis, ＇modern＇ and ＇ancient＇ strains respectively represented 85.5% （324/379） and 14.5% （55/379）. Rv2494 （V48A） and Rv0245 （Sl03F） were confirmed as high differentiation SNPs associated with modern strains. In a word, Modern Beijing lineage M.tuberculosis was dominant and the structural models suggested that modern sub-lineage may more easily survive in ＇extreme＇ host condition.
LI Xiao YingLI YingZHANG YaoKANG Wan LiZHAO Li PingDING Peng JuDAI Wen TaoHUANG Hai RongHUANG Yan FengLI Wei Min
目的 在规范化的结核分枝杆菌（Mycobacterium tuberculosis，MTB）可变数目串联重复序列（variable number of tandem repeats，VNTR）基因分型的基础上，构建我国31个省（自治区、直辖市）VNTR数据库，每个省优化一套VNTR位点组合，为我国结核病预防控制策略的制定提供科学依据。方法 对2007－2008年全国结核病耐药性基线调查的4 116株MTB15位点VNTR（15-VNTR）基因分型。汉高指数（Hunter-Gaston Index，HGI）分析每个位点的分辨率。依据谱系流行特征，以分辨率高和稳定性强为原则，为各省设计一套VNTR优化组合（12-VNTR、10-VNTR、8-VNTR和5-VNTR），采用HGI和成簇率进行评价。结果 完成了涵盖率为96.36%（3 966/4 116）MTB完整15-VNTR图谱。发现QUB11b、MIRU26等7个高分辨率位点；QUB26、MIRU16、Mtub21、QUB11b在部分地区遗传稳定性差。内蒙古自治区、重庆市、黑龙江省的最优组合为10-VNTR，其他各省的最佳组合为8-VNTR。结论 VNTR数据库的建立将推动全国范围MTB传染源的追踪；各省优化VNTR组合的推出有助于当地结核病疫情的监测和群体遗传学的研究。
The genotyping methods of Mycobacterium tuberculosis would dramatically improve our understanding of the molecular epidemiology of tuberculosis. 3,929 isolates, from a National Survey of Drug-Resistant Tuberculosis in 2007 in China, were successfully genotyped by large sequence polymorphisms and 15 loci variable number tandem repeats. We found that 2,905(2,905/3,929, 73.9%) cases belonged to Lineage 2, dominated in the east and central regions, 975 cases(975/3,929, 24.8%) were Lineage 4, highly prevailed in the west regions, and 36 and 13 cases were Lineage 3 and Lineage 1, respectively. We also explored the associations between lineages(Lineage 2 vs. Lineage 4) and clinical characteristics by logistic regression. For Lineage 2, the risk factors were Han-ethnicity population and fever. However, for Lineage 4, they were occupation(farmer), and degree of education(non-literate). Fully understanding of the distribution of Mycobacterium tuberculosis lineage and its risk factors would play a critical role in tuberculosis prevention, control, and treatment.
