Roles of 34 virulence genes in the evolution of hospital- and community-associated strains of methicillin-resistant Staphylococcus aureus
Roles of 34 virulence genes in the evolution of hospital- and community-associated strains of methicillin-resistant Staphylococcus aureus
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DOI：
10.1086/503777
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发表时间：
2006-06-01
影响因子：
6.4
通讯作者：
Perdreau-Remington, F
中科院分区：
文献类型：
--
作者：
Diep, BA;Carleton, HA;Perdreau-Remington, F
背景毒力基因的水平转移在多大程度上促成了医院和社区环境中出现的当代耐甲氧西林金黄色葡萄球菌（MRSA）强毒株。收集了8.5年以上的流行病学特征良好的MRSA分离株进行基因分型，并检测了34个毒力基因的存在。6个菌株型占所有MRSA感染的88.2%。CC 8和CC 30谱系内当代医院和社区表型的演变-产生历史大流行MRSA克隆的2个背景基因组-与毒力基因的多个水平获得相关。CC 8菌株（命名为ST 8：USA 300）的流行性群落表型与获得葡萄球菌盒式染色体（SCC）mec IV型、Panton-Valentine杀白细胞素（PVL）基因以及肠毒素Q和K基因有关。类似地，CC 30菌株ST 30：USA 1100的流行群落表型与SCCmec IV型和pvl基因的获得相关。相反，另一种CC 30菌株ST 36：USA 200的流行性医院表型与获得SCCmec II型、肠毒素A基因和中毒性休克综合征毒素1基因相关。pv 1基因似乎不是其他社区相关MRSA菌株（包括ST 8：USA 500和ST 59：USA 1000）进化所必需的。毒力基因的水平转移虽然不常见，但在流行病学上与MRSA新毒株的出现有关。
Background. The extent to which the horizontal transfer of virulence genes has contributed to the emergence of contemporary virulent strains of methicillin-resistant Staphylococcus aureus (MRSA) in hospital and community settings is poorly understood.Methods. Epidemiologically well-characterized MRSA isolates collected over 8.5 years were genotyped and tested for the presence of 34 virulence genes.Results. Six strain types accounted for 88.2% of all MRSA infections. The evolution of contemporary hospital and community phenotypes within the CC8 and CC30 lineages -2 background genomes that produced historical pandemic MRSA clones - were associated with multiple horizontal acquisitions of virulence genes. The epidemic community phenotype of a CC8 strain, designated ST8:USA300, was linked to the acquisition of staphylococcal cassette chromosome (SCC) mec type IV, the genes for Panton-Valentine leukocidin (PVL), and the enterotoxin Q and K genes. Similarly, the epidemic community phenotype of a CC30 strain, ST30:USA1100, was linked to the acquisition of SCCmec type IV and the pvl genes. In contrast, the epidemic hospital phenotype of another CC30 strain, ST36:USA200, was associated with the acquisition of SCCmec type II, the enterotoxin A gene, and the toxic shock syndrome toxin 1 gene. The pvl genes appear not to be essential for the evolution of other community-associated strains of MRSA, including ST8: USA500 and ST59:USA1000.Conclusions. The horizontal transfer of virulence genes, although infrequent, is epidemiologically associated with the emergence of new virulent strains of MRSA.