Genetic basis of chromosomally-encoded mcr-1 gene
Genetic basis of chromosomally-encoded mcr-1 gene
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DOI：
10.1016/j.ijantimicag.2017.11.015
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发表时间：
2018-04-01
影响因子：
10.8
通讯作者：
Chen, Sheng
中科院分区：
文献类型：
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作者：
Li, Ruichao;Yu, Hua;Chen, Sheng
与质粒携带的mcr-1相比，染色体编码的mcr-1虽然有几例报告，但很少发生。本研究旨在研究大肠埃希菌菌株中染色体编码mcr-1的遗传特征以及控制细菌染色体中mcr-1动员的潜在遗传基础。对16株E.获得并分析含有染色体MCR-1基因的大肠杆菌菌株。系统发育分析和全基因组测序（WGS）分析表明，mcr-1与遗传无关的大肠杆菌染色体上的ISApl 1-mcr 1-orf、Tn 6330、复合体Tn 6330和. Tn 6330等4种主要遗传排列方式相关。大肠杆菌菌株。携带mcr-1的移动的元件显示插入AT富集区，ISApl 1也是如此。对E. coli基因组序列分析表明，ISApl 1在大肠杆菌中存在多拷贝。大肠杆菌染色体也携带mcr-1，而所有mcr-1阴性染色体都不存在ISApl 1的任何拷贝，表明ISApl 1和mcr-1的强关联。将ISApl 1插入E.大肠杆菌染色体可能是插入携带mcr 1的移动的元件的先决条件。将mcr-1插入E.大肠杆菌染色体将使其具有内在抗性，预计这种抗性将变得更加普遍。应在全球范围内实施关于在兽医和临床环境中谨慎使用粘菌素的政策，以进一步预防mcr-1在大肠杆菌中的传播。大肠杆菌和其他细菌病原体。(c)2017 Elsevier B. V.和国际化疗学会。All rights reserved.
Compared with plasmid-borne mcr-1, the occurrence of chromosomally-encoded mcr-1 is rare although it has been reported in several cases. This study aimed to investigate the genetic features of chromosomally-encoded mcr-1 among Escherichia coli strains as well as the potential genetic basis governing mobilisation of mcr-1 in bacterial chromosomes. The genome sequences of 16 E. coli strains containing a chromosomal mcr-1 gene were obtained and analysed. Phylogenetic and whole-genome sequencing (WGS) analysis demonstrated that mcr-1 was associated with four major types of genetic arrangements, namely ISApl1-mcr1-orf, Tn6330, complex Tn6330 and.Tn6330 in chromosomes of genetically unrelated E. coli strains. The mcr-1-carrying mobile elements were shown to insert into the AT-rich region, which was also the case for ISApl1. Analysis of complete E. coli genome sequences showed that there were multiple copies of ISApl1 present in E. coli chromosomes that also carried mcr-1, whilst all mcr-1-negative chromosomes were absent of any copy of ISApl1, suggesting the strong association of ISApl1 and mcr-1. Insertion of ISApl1 into E. coli chromosomes may be a prerequisite for the insertion of mcr1-carrying mobile elements. Insertion of mcr-1 into E. coli chromosomes would enable it to become intrinsically resistant, which is expected to become more prevalent. Policy on the prudent use of colistin both in veterinary and clinical settings should be imposed globally to further prevent dissemination of mcr-1 in E. coli and other bacterial pathogens. (c) 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.