Millet Julie, Miyagi-Shiohira Chika, Yamane Nobuhisa, Sola Christophe, Rastogi Nalin
Unité de la Tuberculose et des Mycobactéries, Institut Pasteur de Guadeloupe, BP484, 97183, Abymes, Guadeloupe.
J Clin Microbiol. 2007 Nov;45(11):3606-15. doi: 10.1128/JCM.00348-07. Epub 2007 Sep 26.
The present investigation focused on genetic diversity and drug resistance of 101 Mycobacterium tuberculosis strains isolated between July 2003 and February 2005 in the Okinawa prefecture, Ryukyu Islands, Japan. A high rate of clustering (87%, eight clusters, 2 to 69 strains/cluster) was observed upon spoligotyping; most of it was due to the lower discriminatory power of this method for the Beijing lineage (n = 72; 71.3% of the isolates). The remaining diversity was limited to seven clusters (two to five isolates/cluster), with the following distribution of major lineages: ill-defined T (n = 13; 12.8%), ancestral East African-Indian (n = 6; 5.9%), Haarlem (n = 4; 4%), Latin American-Mediterranean (n = 2; 2%), X1 (n = 1; 1%), and a total absence of the central Asian clade. Three remaining strains could not be classified on the basis of their spoligotype pattern and were labeled "unknown." Subtyping with mycobacterial interspersed repetitive units (MIRUs) in association with additional QUB minisatellites was performed to discriminate among the Beijing strains. Based on an "in-house" spoligotyping/MIRU database (n = 694 Beijing strains), eight highly discriminative MIRU loci for Beijing strains were selected (loci numbered 10, 16, 23, 26, 27, 31, 39, and 40). The highest discriminatory power (h) observed in our sample (n = 72; M-26, 0.385; M-10, 0.38; M-31, 0.255; M-16, 0.238) was too low, and 73.6% of the Beijing strains from Okinawa remained clustered. Typing of Beijing strains with additional QUB loci (with the exception of "one-copy" QUB-1451) resulted in higher discriminatory powers: QUB-11b, 0.68; QUB-11a, 0.656; QUB-26, 0.644; QUB-18, 0.553; QUB-4156, 0.5; and QUB-1895, 0.453. A definitive algorithm on the use of QUB markers to subtype Beijing isolates in expanded studies would shed light on their hypervariability, which may sometimes blur recognition between epidemiologically linked Beijing isolates. The total absence of multiple drug resistance among Beijing isolates from Okinawa, as well as the relatively older ages of the patients (majority above 60 years), shows that tuberculosis (TB) is a declining disease in Okinawa, and an adequate TB control program has successfully avoided both the emergence and the spread of multidrug-resistant TB in this insular setting.
本研究聚焦于2003年7月至2005年2月间在日本琉球群岛冲绳县分离出的101株结核分枝杆菌的基因多样性和耐药性。通过间隔寡核苷酸分型（spoligotyping）观察到较高的聚类率（87%，8个聚类，每个聚类2至69株）；其中大部分归因于该方法对北京家族菌株（n = 72；占分离株的71.3%）的鉴别力较低。其余的多样性局限于7个聚类（每个聚类2至5株），主要菌系分布如下：未明确的T菌系（n = 13；12.8%）、祖先东非-印度菌系（n = 6；5.9%）、哈勒姆菌系（n = 4；4%）、拉丁美洲-地中海菌系（n = 2；2%）、X1菌系（n = 1；1%），且完全没有中亚分支。其余3株菌株无法根据其间隔寡核苷酸分型模式进行分类，被标记为“未知”。为了区分北京菌株，进行了结核分枝杆菌散布重复单元（MIRUs）与额外的QUB微卫星联合分型。基于一个“内部”间隔寡核苷酸分型/MIRU数据库（n = 694株北京菌株），为北京菌株选择了8个高鉴别力的MIRU位点（位点编号10、16、23、26、27、31、39和40）。在我们的样本（n = 72）中观察到的最高鉴别力（h）过低（M-26为0.385；M-10为0.38；M-31为0.255；M-16为0.238），来自冲绳的73.6%的北京菌株仍处于聚类状态。用额外的QUB位点（除“单拷贝”QUB-1451外）对北京菌株进行分型，鉴别力更高：QUB-11b为0.68；QUB-11a为0.656；QUB-26为与644；QUB-18为0.553；QUB-4156为0.5；QUB-1895为0.453。在扩展研究中使用QUB标记对北京分离株进行亚型分型的明确算法，将有助于揭示其高度变异性，这种变异性有时可能会模糊在流行病学上相关的北京分离株之间的识别。来自冲绳的北京分离株中完全没有多重耐药情况，以及患者年龄相对较大（大多数超过60岁），表明结核病在冲绳是一种发病率正在下降的疾病，并且一个适当的结核病控制项目已成功避免了多重耐药结核病在这个岛屿环境中的出现和传播。
