Novel staphylococcal cassette chromosome mec (SCCmec) type XIV (5A) and a truncated SCCmec element in SCC composite islands carrying speG in ST5 MRSA in Japan
Novel staphylococcal cassette chromosome mec (SCCmec) type XIV (5A) and a truncated SCCmec element in SCC composite islands carrying speG in ST5 MRSA in Japan
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DOI：
10.1093/jac/dkz406
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发表时间：
2020-01-01
影响因子：
5.2
通讯作者：
Kobayashi, Nobumichi
中科院分区：
文献类型：
--
作者：
Urushibara, Noriko;Aung, Meiji Soe;Kobayashi, Nobumichi
背景：葡萄球菌盒式染色体mec（SCCmec）元件具有高度多样性，目前已被分为13种类型。精氨酸分解代谢移动的元件（ACME）是一个含有精氨酸脱亚胺酶途径基因簇（ACME-arc）的SCC样元件。ACME I型（ACME I），另外包括亚精胺/精胺-N-1-乙酰转移酶基因（speG），被认为是促成了最成功的MRSA克隆USA 300的快速传播。目的：描述ACME-arc和speG均阳性的ST 5 MRSA中SCC复合岛（SCC-CI）的特征。3株ST 5 MRSA菌株对采自日本北海道的三个品种（SC 640、SC 792和SC 955）进行WGS，测定SCC-CI。SCC-CI由四个（SC 640和SC 792）或三个（SC 955）SCC/SCC样元件组成，通常含有ACME II'型和SCC编码speG。这些SCC-CI似乎模仿了USA 300中的ACME I，因为它们配备了ACME-arc和speG。SC 640和SC 792的SCC-CI在3'端含有新的SCCmec/SCCmec样元件，而SC 955含有SCCmec V型。SC 792的SCCmec携带mec复合物A和ccrCl，其被确定为是新的并被命名为SCCmec XIV型（5A）。SC 640具有SCCmec-样元件，其来源于SCCmec类型XIV。该基因缺失了mec复合物的大部分下游区域，包括左侧染色体附着位点（SCCmec XIV Akdp/DR-L），失去了对染色体的切割能力，提示mecA基因被固定在染色体上。
Background: Staphylococcal cassette chromosome mec (SCCmec) elements are highly diverse and have been classified into 13 types. The arginine catabolic mobile element (ACME) is an SCC-Like element harbouring an arginine deiminase pathway gene cluster (ACME-arc). ACME type I (ACME I), additionally including a spermidine/ spermine-N-1-acetyltransferase gene (speG), is considered to have contributed to the rapid spread of the most successful MRSA clone, USA300.Objectives: To characterize the SCC composite islands (SCC-CIs) in ST5 MRSA positive for both ACME-arc and speG.Methods: Three ST5 MRSA strains (SC640, SC792 and SC955) collected in Hokkaido, Japan were subjected to WGS and the SCC-CIs were determined.Results: The SCC-CIs consisted of four (SC640 and SC792) or three (SC955) SCC/SCC-Like elements and commonly harboured both an ACME type II' and an SCC encoding speG. These SCC-CIs appear to mimic ACME I in USA300, in that they are equipped with ACME-arc and speG. The SCC-CIs of SC640 and SC792 contained novel SCCmec/ SCCmec-Like elements at the 3' end, whereas SC955 contained SCCmec type V. The SCCmec of SC792 carried mec complex A and ccrC1, which was determined to be novel and designated as SCCmec type XIV (5A). SC640 harboured an SCCmec-Like element derived from SCCmec type XIV. It Lacked most of the downstream region of the mec complex, including the Left chromosomal attachment site (SCCmec XIV Akdp/DR-L), and Lost its capability for chromosomal excision, suggesting that the mecA gene is immobilized on the chromosome.Conclusions: These findings provide evidence for increasing complexity of SCC-CIs.