Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, Trinity College, University of Dublin, Dublin, Ireland.
National MRSA Reference Laboratory, St. James's Hospital, James's Street, Dublin, Ireland.
Infect Genet Evol. 2019 Apr;69:117-126. doi: 10.1016/j.meegid.2019.01.021. Epub 2019 Jan 21.
This study investigated the recent emergence of multidrug-resistant Panton-Valentine leukocidin (PVL)-negative CC1-MRSA-IV in Ireland and Germany. Ten CC1-MSSA and 139 CC1-MRSA isolates recovered in Ireland between 2004 and 2017 were investigated. These were compared to 21 German CC1-MRSA, 10 Romanian CC1-MSSA, five Romanian CC1-MRSA and two UAE CC1-MRSA, which were selected from an extensive global database, based on similar DNA microarray profiles to the Irish isolates. All isolates subsequently underwent whole-genome sequencing, core-genome single nucleotide polymorphism (cgSNP) analysis and enhanced SCCmec subtyping. Two PVL-negative clades (A and B1) were identified among four main clades. Clade A included 20 German isolates, 119 Irish isolates, and all Romanian MRSA and MSSA isolates, the latter of which differed from clade A MRSA by 47-130 cgSNPs. Eighty-six Irish clade A isolates formed a tight subclade (A1) exhibiting 0-49 pairwise cgSNPs, 80 of which harboured a 46 kb conjugative plasmid carrying both ileS2, encoding high-level mupirocin resistance, and qacA, encoding chlorhexidine resistance. The resistance genes aadE, aphA3 and sat were detected in all clade A MRSA and the majority (8/10) of clade A MSSA isolates. None of the clade A isolates harboured any enterotoxin genes other than seh, which is universally present in CC1. Clade B1 included the remaining German isolate, 17 Irish isolates and the two UAE isolates, all of which corresponded to the Western Australia MRSA-1 (WA MRSA-1) clone based on genotypic characteristics. MRSA within clades A and B1 differed by 188 cgSNPs and clade-specific SCCmec characteristics were identified, indicating independent acquisition of the SCCmec element. This study demonstrated the existence of a European PVL-negative CC1-MRSA-IV clone that is distinctly different from the well-defined PVL-negative CC1-MRSA-IV clone, WA MRSA-1. Furthermore, cgSNP analysis revealed that this newly defined clone may have originated in South-Eastern Europe, before spreading to both Ireland and Germany.
本研究调查了最近在爱尔兰和德国出现的耐多药潘顿-瓦伦丁白细胞毒素（PVL）阴性 CC1-MRSA-IV。2004 年至 2017 年间，在爱尔兰共检测到 10 株 CC1-MSSA 和 139 株 CC1-MRSA 分离株。将这些分离株与来自广泛的全球数据库的 21 株德国 CC1-MRSA、10 株罗马尼亚 CC1-MSSA、5 株罗马尼亚 CC1-MRSA 和 2 株阿联酋 CC1-MRSA 进行比较，这些分离株的 DNA 微阵列图谱与爱尔兰分离株相似。所有分离株随后进行全基因组测序、核心基因组单核苷酸多态性（cgSNP）分析和增强型 SCCmec 亚型分析。在四个主要的 CC1-MRSA 分支中，确定了两个 PVL 阴性分支（A 和 B1）。分支 A 包括 20 株德国分离株、119 株爱尔兰分离株和所有罗马尼亚的 MRSA 和 MSSA 分离株，后者与分支 A 的 MRSA 相差 47-130 cgSNPs。86 株爱尔兰分支 A 分离株形成一个紧密的亚分支（A1），其具有 0-49 对 cgSNPs，其中 80 株含有携带高水平 mupirocin 抗性的 ileS2 和编码氯己定抗性的 qacA 的 46kb 可接合质粒。所有分支 A 的 MRSA 和大多数（8/10）分支 A 的 MSSA 分离株都检测到 aadE、aphA3 和 sat 耐药基因。除了在 CC1 中普遍存在的 seh 外，分支 A 的分离株均未携带任何肠毒素基因。分支 B1 包括其余的德国分离株、17 株爱尔兰分离株和 2 株阿联酋分离株，所有这些分离株均基于基因型特征与西澳大利亚 MRSA-1（WA MRSA-1）克隆相对应。分支 A 和 B1 中的 MRSA 相差 188 cgSNPs，并且鉴定了分支特异性的 SCCmec 特征，表明 SCCmec 元件的独立获得。本研究表明，存在一种明显不同于明确定义的 PVL 阴性 CC1-MRSA-IV 克隆（WA MRSA-1）的欧洲 PVL 阴性 CC1-MRSA-IV 克隆。此外，cgSNP 分析表明，这个新定义的克隆可能起源于东南欧，然后传播到爱尔兰和德国。
