Detection of a previously unamplified spacer within the DR locus of Mycobacterium tuberculosis:: Epidemiological implications
Detection of a previously unamplified spacer within the DR locus of Mycobacterium tuberculosis:: Epidemiological implications
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DOI：
10.1128/jcm.38.3.1231-1234.2000
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发表时间：
2000-03-01
影响因子：
9.4
通讯作者：
Rastogi, N
中科院分区：
文献类型：
--
作者：
Filliol, I;Sola, C;Rastogi, N
Spoligotyping是一种基于结核分枝杆菌（Mycobacterium tuberculosis）和牛结核分枝杆菌（Mycobacterium bovis BCG）的43个DR间隔区（inter-direct repeat，inter-direct repeat）分布变异性的方法，可用于研究牛和人结核病的分子流行病学。最近，M.在一项多中心研究中报道了命名为哈勒姆家族的结核病临床分离株，其不含间隔子31和33至36。独立地，包含所有已发表的spoligotypes的数据库显示，世界上最流行的两种spoligotypes的差异仅在于间隔区31的存在或不存在。DR位点序列的仔细分析使我们假设，间隔区31可能没有扩增在一些分离物与引物组DRa和DRb目前用于spoligotyping。因此，设计了基于36-bp DR和IS 6110引物的不同组合的改进的spoligotyping方法，其能够区分DR基因座的左和右部分，并且证明了对于一些临床分离株存在先前未扩增的间隔区31。通过类比，我们认为，在一些流行病学相关的结核病病例中，可能仅仅是由于在DR位点内插入了额外的IS 6110拷贝，导致其不对称破坏和随后缺乏DRa或DRb靶点而产生单间隔区差异。DR位点内IS 6110优先插入位点对Spoligotyping结果的影响有待进一步研究。
Spoligotyping, a method based on the variability of distribution of the 43 inter-direct repeat (DR) spacers of Mycobacterium tuberculosis and Mycobacterium bovis BCG, is useful to study the molecular epidemiology of bovine and human tuberculosis. Recently, a major family of M. tuberculosis clinical isolates named the Haarlem family, which did not contain spacers 31 and 33 to 36, was reported in a multicenter study. Independently, a data bank containing all the published spoligotypes showed that the two most prevalent spoligotypes in the world differed only by the presence or absence of spacer 31. A careful analysis of the DR locus sequence led us to hypothesize that spacer 31 may not have been amplified in some isolates with the primer sets DRa and DRb currently used for spoligotyping. Consequently, a modified spoligotyping method based on different combinations of the 36-bp DR and IS6110 primers was devised that was able to discriminate between the left and the right parts of the DR locus and demonstrated the presence of the previously unamplified spacer 31 for some of the clinical isolates. By analogy, we suggest that a single-spacer difference in some epidemiologically linked cases of tuberculosis may simply arise due to the insertion of an extra copy of IS6110 within the DR locus, leading to its asymmetrical disruption and subsequent lack of the DRa or DRb targets. The influence of the IS6110 preferential insertion sites within the DR locus on spoligotyping results should be further investigated.