van Soolingen D, de Haas P E, Hermans P W, Groenen P M, van Embden J D
Unit Molecular Microbiology, National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands.
J Clin Microbiol. 1993 Aug;31(8):1987-95. doi: 10.1128/jcm.31.8.1987-1995.1993.
Five different genetic elements have been found to be associated with genetic rearrangements in Mycobacterium tuberculosis complex strains. Of these elements, the insertion sequence IS6110 is presently the most frequently used genetic marker for strain differentiation of M. tuberculosis. In the present study we compared five genetic elements for their potentials to differentiate a given cluster of M. tuberculosis strains. Because of the presence of only a single copy of IS6110 or two IS6110 copies at the same chromosomal locus, a large number of strains could not be differentiated by IS6110 fingerprinting. Most strains, including the low-copy-number IS6110 strains, could be differentiated by fingerprinting with the 36-bp direct repeat or the polymorphic GC-rich repetitive DNA element. Less discriminative power was obtained with the major polymorphic tandem repeat and the insertion element IS1081. One strain which did not contain IS6110 DNA was encountered. Until now, this element has invariantly been found to be present in all M. tuberculosis complex strains. On the basis of classical taxonomic criteria and sequencing of the 16S rRNA gene, this strain was shown to be a genuine M. tuberculosis strain. Therefore, the use of this element as a target for polymerase chain reaction-facilitated detection of M. tuberculosis should be reconsidered.
已发现五种不同的遗传元件与结核分枝杆菌复合群菌株的基因重排有关。在这些元件中，插入序列IS6110目前是用于结核分枝杆菌菌株鉴别最常用的遗传标记。在本研究中，我们比较了五种遗传元件区分特定结核分枝杆菌菌株簇的潜力。由于在同一染色体位点仅存在单拷贝的IS6110或两个IS6110拷贝，大量菌株无法通过IS6110指纹图谱进行区分。大多数菌株，包括低拷贝数的IS6110菌株，可通过36 bp直接重复序列或富含GC的多态性重复DNA元件的指纹图谱进行区分。主要多态性串联重复序列和插入元件IS1081的鉴别能力较低。遇到了一株不含IS6110 DNA的菌株。迄今为止，在所有结核分枝杆菌复合群菌株中均始终发现该元件存在。根据经典分类标准和16S rRNA基因测序，该菌株被证明是一株真正的结核分枝杆菌菌株。因此，应重新考虑将该元件用作聚合酶链反应辅助检测结核分枝杆菌的靶标。
