Insights on evolution of virulence and resistance from the whole-genome analysis of a predominant methicillin-resistant Staphylococcus aureus clone sequence type 239 in China
Insights on evolution of virulence and resistance from the whole-genome analysis of a predominant methicillin-resistant Staphylococcus aureus clone sequence type 239 in China
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DOI：
10.1007/s11434-014-0149-1
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发表时间：
2014-04-01
影响因子：
--
通讯作者：
Wang, Hui
中科院分区：
文献类型：
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作者：
Chen, Hongbin;Yang, Xi;Wang, Hui
此前，我们曾报道 ST239 是中国 15 年主要的耐甲氧西林金黄色葡萄球菌 (MRSA) 克隆。本研究采用从血液中分离的属于ST239的MRSA菌株CN79来测定全基因组序列。在 MRSA CN79 和 NCBI GenBank 数据库中的 25 个已测序金黄色葡萄球菌之间进行了比较基因组学分析。 MRSA CN79基因组中总共鉴定出2,734个蛋白质编码基因，其中携带11个抗生素抗性基因和65个毒力基因。在 MRSA CN79 基因组上发现了两种前噬菌体 phiCN79A 和 phiNM3-like。 MRSA CN79 携带 25 个已测序的金黄色葡萄球菌基因组中不存在的 30 个特定基因。其中大多数是原噬菌体相关基因。一些抗生素耐药基因，如β-内酰胺酶和ABC型多药转运系统基因，位于基因组岛nu Sa beta上。抗生素抗性基因，如tet (M)、ermA1和blaZ，也位于不同的转座子上。毒力基因sea、map、hlb和sak位于phiNM3样原噬菌体上，外毒素基因位于基因组岛nu Sa α上。这些结果表明，ST239 MRSA菌株之所以广泛传播，是因为在进化过程中水平获得了可移动遗传元件，其中包含抗生素抗性基因和毒力基因，以应对环境选择压力，例如抗生素和人类免疫系统。
Earlier, we reported that ST239 was the 15-year predominant methicillin-resistant Staphylococcus aureus (MRSA) clone in China. In this study, MRSA strain CN79 belonging to ST239 and isolated from blood was used to determine the whole genome sequence. Comparative genomics analysis was done between MRSA CN79 and 25 sequenced S. aureus in the NCBI GenBank database. A total of 2,734 protein-encoding genes were identified in the MRSA CN79 genome, which carries 11 antibiotic resistance genes and 65 virulence genes. Two prophages phiCN79A and phiNM3-like were found on the MRSA CN79 genome. MRSA CN79 carries 30 specific genes that are absent from the 25 sequenced S. aureus genomes. Most of them were prophage-related genes. Several antibiotic resistance genes, such as beta-lactamase and ABC-type multidrug transport system gene, were located on the genomic island nu Sa beta. The antibiotic resistance genes, such as tet (M), ermA1, and blaZ, were also located on different transposons. The virulence genes sea, map, hlb, and sak are located on phiNM3-like prophage and the exotoxin genes are carried on the genomic island nu Sa alpha. These results suggest that ST239 MRSA strains are widespread owing to horizontal acquisition of the mobile genetic elements harbored antibiotic resistance genes and virulence genes in response to environmental selective pressures, such as antibiotics and the human immune system during evolution.