Blackwood K S, Turenne C Y, Harmsen D, Kabani A M
National Reference Centre for Mycobacteriology, National Microbiology Laboratory, Population and Public Health Branch, Health Canada.
J Clin Microbiol. 2004 Apr;42(4):1626-30. doi: 10.1128/JCM.42.4.1626-1630.2004.
The Bacillus genus is a large heterogeneous group in need of an efficient method for species differentiation. To determine the current validity of a sequence-based method for identification and provide contemporary data, PCR and sequencing of a 500-bp product encompassing the V1 to V3 regions of the 16S rRNA gene were undertaken using 65 of the 83 type strains of this genus. This region proved discriminatory between most species (70.0 to 100% similarity), the exceptions being clinically relevant B. cereus and B. anthracis as well as nonpathogenic B. psychrotolerans and B. psychrodurans. Consequently, 27 type and clinical strains from the B. cereus group were used to test alternate targets (rpoB, vrrA, and the 16S-23S spacer region) for identification. The rpoB gene proved the best alternate target, with a conserved 4-nucleotide difference between B. cereus and B. anthracis. The high 16S rRNA gene sequence similarities between some strains demonstrated the need for a polyphasic approach to the systematics of this genus. This approach is one focus of the Ribosomal Differentiation of Medical Microorganisms mandate. Accordingly, the 16S rRNA gene sequences generated in this study have been submitted for inclusion into its publicly accessible, quality-controlled database at http://www.ridom_rdna.de/.
芽孢杆菌属是一个庞大的异质菌群，需要一种有效的物种区分方法。为了确定基于序列的鉴定方法的当前有效性并提供当代数据，我们使用了该属83个模式菌株中的65个，对包含16S rRNA基因V1至V3区域的500bp产物进行了PCR和测序。该区域在大多数物种之间具有鉴别性（相似度为70.0%至100%），临床相关的蜡样芽孢杆菌和炭疽芽孢杆菌以及非致病性的耐冷芽孢杆菌和嗜冷芽孢杆菌除外。因此，我们使用了蜡样芽孢杆菌组的27个模式菌株和临床菌株来测试用于鉴定的替代靶标（rpoB、vrrA和16S-23S间隔区）。rpoB基因被证明是最佳的替代靶标，蜡样芽孢杆菌和炭疽芽孢杆菌之间存在4个保守的核苷酸差异。一些菌株之间16S rRNA基因序列的高度相似性表明，需要采用多相方法来研究该属的系统发育。这种方法是“医学微生物核糖体分化”任务的一个重点。因此，本研究中生成的16S rRNA基因序列已提交至http://www.ridom_rdna.de/ 其公开可用的、质量受控的数据库中。
