Rolo Joana, Worning Peder, Nielsen Jesper Boye, Bowden Rory, Bouchami Ons, Damborg Peter, Guardabassi Luca, Perreten Vincent, Tomasz Alexander, Westh Henrik, de Lencastre Hermínia, Miragaia Maria
Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
Laboratory of Bacterial Evolution and Molecular Epidemiology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
Antimicrob Agents Chemother. 2017 May 24;61(6). doi: 10.1128/AAC.02302-16. Print 2017 Jun.
Several lines of evidence indicate that the most primitive staphylococcal species, those of the group, were involved in the first stages of evolution of the staphylococcal cassette chromosome (SCC), the genetic element carrying the β-lactam resistance gene However, many steps are still missing from this evolutionary history. In particular, it is not known how was incorporated into the mobile element SCC prior to dissemination among and other pathogenic staphylococcal species. To gain insights into the possible contribution of several species of the group to the assembly of SCC, we sequenced the genomes of 106 isolates, comprising ( = 76), ( = 18), and ( = 12) from animal and human sources, and characterized the native location of and the SCC insertion site by using a variety of comparative genomic approaches. Moreover, we performed a single nucleotide polymorphism (SNP) analysis of the genomes in order to understand SCC evolution in relation to phylogeny. We found that each of three species of the group contributed to the evolution of SCC: and contributed to the assembly of the complex, and most likely provided the mobile element in which was later incorporated. We hypothesize that an ancestral SCC III cassette (an element carried by one of the most epidemic methicillin-resistant clones) originated in possibly by a recombination event in a human host or a human-created environment and later was transferred to .
多条证据表明，最原始的葡萄球菌种类，即该组中的那些种类，参与了葡萄球菌盒式染色体（SCC）进化的最初阶段，SCC是携带β-内酰胺抗性基因的遗传元件。然而，这段进化史中仍有许多环节缺失。特别是，尚不清楚在其于该组及其他致病性葡萄球菌物种中传播之前，是如何被整合到移动元件SCC中的。为了深入了解该组的几种葡萄球菌对SCC组装可能做出的贡献，我们对106株分离株的基因组进行了测序，这些分离株包括来自动物和人类来源的（=76）、（=18）和（=12），并通过多种比较基因组学方法对的天然位置和SCC插入位点进行了表征。此外，我们对基因组进行了单核苷酸多态性（SNP）分析，以了解SCC相对于系统发育的进化情况。我们发现该组的三种葡萄球菌中的每一种都对SCC的进化做出了贡献：和促成了复合体的组装，而最有可能提供了后来被整合进去的移动元件。我们推测，一个祖先的SCC III盒式元件（一种由最流行的耐甲氧西林克隆之一携带的元件）可能起源于人类宿主或人类创造的环境中的重组事件，随后被转移到了。
