Kim Byoung-Jun, Kim Ga-Na, Kim Bo-Ram, Jeon Che Ok, Jeong Joseph, Lee Seon Ho, Lim Ji-Hun, Lee Seung-Heon, Kim Chang Ki, Kook Yoon-Hoh, Kim Bum-Joon
Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea.
School of Biological Sciences, Chung-Ang University, Seoul, Republic of Korea.
Int J Syst Evol Microbiol. 2017 Oct;67(10):3882-3887. doi: 10.1099/ijsem.0.002217. Epub 2017 Sep 12.
Three rapidly growing mycobacterial strains, QIA-37, QIA-40 and QIA-41, were isolated from the lymph nodes of three separate Korean native cattle, Hanwoo (Bos taurus coreanae). These strains were previously shown to be phylogenetically distinct but closely related to Mycobacterium chelonae ATCC 35752 by taxonomic approaches targeting three genes (16S rRNA, hsp6 and rpoB) and were further characterized using a polyphasic approach in this study. The 16S rRNA gene sequences of all three strains showed 99.7 % sequence similarity with that of the M. chelonae type strain. A multilocus sequence typing analysis targeting 10 housekeeping genes, including hsp65 and rpoB, revealed a phylogenetic cluster of these strains with M. chelonae. DNA-DNA hybridization values of 78.2 % between QIA-37 and M. chelonae indicated that it belongs to M. chelonae but is a novel subspecies distinct from M. chelonae. Phylogenetic analysis based on whole-genome sequences revealed a 95.44±0.06 % average nucleotide identity (ANI) value with M. chelonae, slightly higher than the 95.0 % ANI criterion for determining a novel species. In addition, distinct phenotypic characteristics such as positive growth at 37 °C, at which temperature M. chelonae does not grow, further support the taxonomic status of these strains as representatives of a novel subspecies of M. chelonae. Therefore, we propose an emended description of Mycobacterium chelonae, and descriptions of M. chelonae subsp. chelonae subsp. nov. and M. chelonae subsp. bovis subsp. nov. are presented; strains ATCC 35752(=CCUG 47445=CIP 104535=DSM 43804=JCM 6388=NCTC 946) and QIA-37 (=KCTC 39630=JCM 30986) are the type strains of the two novel subspecies.
从三头韩国本土牛（韩牛，Bos taurus coreanae）的淋巴结中分离出三株快速生长的分枝杆菌菌株，即QIA - 37、QIA - 40和QIA - 41。通过针对三个基因（16S rRNA、hsp6和rpoB）的分类学方法，先前已表明这些菌株在系统发育上是不同的，但与龟分枝杆菌ATCC 35752密切相关。在本研究中，使用多相分类法对这些菌株进行了进一步表征。所有三株菌株的16S rRNA基因序列与龟分枝杆菌模式菌株的序列相似性为99.7%。针对包括hsp65和rpoB在内的10个管家基因的多位点序列分型分析表明，这些菌株与龟分枝杆菌形成一个系统发育簇。QIA - 37与龟分枝杆菌之间的DNA - DNA杂交值为78.2%，表明它属于龟分枝杆菌，但却是与龟分枝杆菌不同的一个新亚种。基于全基因组序列的系统发育分析显示，其与龟分枝杆菌的平均核苷酸同一性（ANI）值为95.44±0.06%，略高于确定新物种的95.0%的ANI标准。此外，这些菌株具有独特的表型特征，如在37°C能生长，而龟分枝杆菌在此温度下不能生长，这进一步支持了这些菌株作为龟分枝杆菌一个新亚种代表的分类地位。因此，我们提出了对龟分枝杆菌的修订描述，并给出了龟分枝杆菌龟亚种新亚种和龟分枝杆菌牛亚种新亚种的描述；菌株ATCC 35752(=CCUG 47445=CIP 104535=DSM 43804=JCM 6388=NCTC 946)和QIA - 37(=KCTC 39630=JCM 30986)是这两个新亚种的模式菌株。
