Sun Yong-Jiang, Lee Ann S G, Ng Sze Ta, Ravindran Sindhu, Kremer Kristin, Bellamy Richard, Wong Sin-Yew, van Soolingen Dick, Supply Philip, Paton Nicholas I
Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore 308433.
J Clin Microbiol. 2004 Nov;42(11):5058-64. doi: 10.1128/JCM.42.11.5058-5064.2004.
Sixty-eight ancestral Mycobacterium tuberculosis isolates were previously identified by using the tuberculosis-specific deletion 1 (TbD1) PCR and mycobacterial interspersed-repetitive-unit-variable-number tandem repeat (MIRU-VNTR) typing (Y. J. Sun, R. Bellamy, A. S. G. Lee, S. T. Ng, S. Ravindran, S.-Y. Wong, C. Locht, P. Supply, and N. I. Paton, J. Clin. Microbiol. 42:1986-1993, 2004). These TbD1(+) ancestral isolates were further characterized and typed in this study by IS6110 restriction fragment length polymorphism (RFLP) typing, VNTR typing using exact tandem repeats (VNTR-ETR), and spoligotyping of the direct-repeat region. To our knowledge, this is the first characterization of this genogroup by multiple genetic markers based on a fairly large sample size. In this genogroup, all spoligotypes were characterized by the absence of spacers 29 to 32 and 34. In addition, VNTR-ETR typing could add further resolution to the clustered isolates identified by MIRU-VNTR, and the combination of MIRU-VNTR and VNTR-ETR, called MIRU-ETR, showed the highest discriminatory power for these strains compared to IS6110 RFLP typing and spoligotyping alone. However, MIRU-ETR appeared to still cluster some probably epidemiologically unrelated strains, as judged by IS6110 RFLP divergence. Therefore, a typing strategy based on stepwise combination of MIRU-ETR and IS6110 RFLP is proposed to achieve maximal discrimination for unrelated TbD1(+) strains. This typing strategy may be useful in areas where TbD1(+) ancestral strains are prevalent.
先前通过结核特异性缺失1（TbD1）PCR和分枝杆菌散布重复单元可变数目串联重复序列（MIRU-VNTR）分型鉴定出68株结核分枝杆菌祖先菌株（Y. J. 孙、R. 贝拉米、A. S. G. 李、S. T. 吴、S. 拉温德兰、S.-Y. 黄、C. 洛克特、P. 苏皮、N. I. 帕顿, 《临床微生物学杂志》42:1986 - 1993, 2004年）。在本研究中，通过IS6110限制性片段长度多态性（RFLP）分型、使用精确串联重复序列的VNTR分型（VNTR-ETR）以及直接重复区域的间隔寡核苷酸分型（spoligotyping）对这些TbD1(+)祖先菌株进行了进一步表征和分型。据我们所知，这是基于相当大的样本量，首次使用多种遗传标记对该基因群进行表征。在这个基因群中，所有间隔寡核苷酸分型的特征都是缺少间隔区29至32和34。此外，VNTR-ETR分型可以进一步区分MIRU-VNTR鉴定出的聚集菌株，与单独的IS6110 RFLP分型和间隔寡核苷酸分型相比，MIRU-VNTR和VNTR-ETR的组合，即MIRU-ETR，对这些菌株显示出最高的鉴别力。然而，根据IS6110 RFLP差异判断，MIRU-ETR似乎仍将一些可能在流行病学上不相关的菌株聚集在一起。因此，提出了一种基于MIRU-ETR和IS6110 RFLP逐步组合的分型策略，以实现对不相关TbD1(+)菌株的最大鉴别。这种分型策略可能在TbD1(+)祖先菌株流行的地区有用。
