Centre for Infection, Department of Cellular and Molecular Medicine, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
Int J Med Microbiol. 2010 Feb;300(2-3):98-103. doi: 10.1016/j.ijmm.2009.08.013. Epub 2009 Oct 7.
The evolution of new human and animal pathogenic strains of Staphylococcus aureus has been due to the accumulation of mobile genetic elements (MGE) encoding methicillin resistance and virulence factors into successful lineages. These include epidemic methicillin-resistant S. aureus in hospitals (EMRSA), community-associated MRSA (CA-MRSA), fully vancomycin-resistant MRSA (VRSA) and livestock-associated MRSA (LA-MRSA). The S. aureus population in humans is dominated by about ten S. aureus lineages while animals generally have different lineages. Individual isolates within each lineage have unique combination of MGE often encoding virulence and resistance genes. S. aureus evolves due to point mutation and selection, but also dramatically due to the horizontal transfer of these MGE between strains or from other species or genera. Horizontal transfer, by conjugation or transduction, can be blocked by S. aureus restriction modification systems which are lineage specific. Because of the mobility of MGE, there are prospects for increasingly virulent and resistant strains to emerge that could severely affect healthcare and agriculture more effectively than the current pathogens.
金黄色葡萄球菌新的人类和动物病原体菌株的进化是由于编码耐甲氧西林和毒力因子的可移动遗传元件（MGE）积累到成功的谱系中。这些包括医院中的流行耐甲氧西林金黄色葡萄球菌（EMRSA）、社区相关耐甲氧西林金黄色葡萄球菌（CA-MRSA）、完全万古霉素耐药金黄色葡萄球菌（VRSA）和与牲畜相关的耐甲氧西林金黄色葡萄球菌（LA-MRSA）。人类中的金黄色葡萄球菌种群主要由大约十个金黄色葡萄球菌谱系组成，而动物通常具有不同的谱系。每个谱系内的单个分离株具有独特的 MGE 组合，通常编码毒力和耐药基因。金黄色葡萄球菌由于点突变和选择而进化，但也由于这些 MGE 在菌株之间或来自其他物种或属之间的水平转移而急剧进化。通过接合或转导进行的水平转移可以被金黄色葡萄球菌限制修饰系统阻断，该系统是谱系特异性的。由于 MGE 的可移动性，有可能出现越来越毒力和耐药的菌株，这些菌株比当前的病原体更有效地严重影响医疗保健和农业。
