Ramsay Joshua P, Kwong Stephen M, Murphy Riley J T, Yui Eto Karina, Price Karina J, Nguyen Quang T, O'Brien Frances G, Grubb Warren B, Coombs Geoffrey W, Firth Neville
School of Biomedical Sciences and Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia; ACCESS Typing and Research, School of Veterinary Sciences and Life Sciences, Murdoch University and School of Biomedical Sciences, Curtin University, Perth, WA, Australia.
School of Life and Environmental Sciences, University of Sydney , Sydney, NSW, Australia.
Mob Genet Elements. 2016 Jul 1;6(4):e1208317. doi: 10.1080/2159256X.2016.1208317. eCollection 2016 Jul-Aug.
The horizontal gene transfer facilitated by mobile genetic elements impacts almost all areas of bacterial evolution, including the accretion and dissemination of antimicrobial-resistance genes in the human and animal pathogen Staphylococcus aureus. Genome surveys of staphylococcal plasmids have revealed an unexpected paucity of conjugation and mobilization loci, perhaps suggesting that conjugation plays only a minor role in the evolution of this genus. In this letter we present the DNA sequences of historically documented staphylococcal conjugative plasmids and highlight that at least 3 distinct and widely distributed families of conjugative plasmids currently contribute to the dissemination of antimicrobial resistance in Staphylococcus. We also review the recently documented "relaxase-in trans" mechanism of conjugative mobilization facilitated by conjugative plasmids pWBG749 and pSK41, and discuss how this may facilitate the horizontal transmission of around 90% of plasmids that were previously considered non-mobilizable. Finally, we enumerate unique sequenced S. aureus plasmids with a potential mechanism of mobilization and predict that at least 80% of all non-conjugative S. aureus plasmids are mobilizable by at least one mechanism. We suggest that a greater research focus on the molecular biology of conjugation is essential if we are to recognize gene-transfer mechanisms from our increasingly in silico analyses.
由可移动遗传元件促成的水平基因转移几乎影响了细菌进化的所有领域，包括人类和动物病原体金黄色葡萄球菌中抗菌抗性基因的积累和传播。葡萄球菌质粒的基因组调查显示，接合和动员位点出乎意料地稀少，这或许表明接合在该属的进化中仅起次要作用。在这封信中，我们展示了历史记录的葡萄球菌接合质粒的DNA序列，并强调目前至少有3个不同且广泛分布的接合质粒家族在金黄色葡萄球菌中促成了抗菌抗性的传播。我们还回顾了最近记录的由接合质粒pWBG749和pSK41促成的“反式松弛酶”接合动员机制，并讨论了这一机制如何促进约90%以前被认为不可移动的质粒的水平传播。最后，我们列举了具有潜在动员机制的独特测序金黄色葡萄球菌质粒，并预测所有非接合金黄色葡萄球菌质粒中至少80%可通过至少一种机制进行移动。我们认为，如果我们要从日益增多的计算机分析中识别基因转移机制，加大对接合分子生物学的研究力度至关重要。
