Complete sequencing of an IncX3 plasmid carrying blaNDM-5 allele reveals an early stage in the dissemination of the blaNDM gene
Complete sequencing of an IncX3 plasmid carrying blaNDM-5 allele reveals an early stage in the dissemination of the blaNDM gene
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DOI：
10.4103/0255-0857.148373
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发表时间：
2015-01-01
影响因子：
1.6
通讯作者：
Vaidyanathan, R.
中科院分区：
文献类型：
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作者：
Krishnaraju, M.;Kamatchi, C.;Vaidyanathan, R.
目的：本研究的目的是对BLA(NDM)质粒进行分子鉴定，并了解其在病原菌中传播的机制。材料和方法：收集金奈地区4家医院2011年11月至2013年4月分离的76株非重复碳青霉烯类耐药菌株，采用聚合酶链式反应(PCR)方法检测BLA(NDM)基因。进一步，利用ISAba125和ble(MBL)基因特异的聚合酶链式反应分析了bla(NDM)基因的遗传背景。在Illumina HiSeq平台上对其中一个BLA(NDM)质粒进行了全序列测定。结果：检出携带blA(Ndm)基因的23株细菌，其中大肠埃希菌8株，肺炎克雷伯菌8株，产酸克雷伯菌3株，鲍曼不动杆菌3株，铜绿假单胞菌1株。在18个分离株中，bla(NDM)基因与ble(MBL)基因和ISAba125元件相关。PNDM-MGR194全序列分析显示为IncX3复制型，全长46,253个碱基，平均GC含量为47%，推测为59个ORF。Iteron区下游含有bla(NDM5)基因和ble(MBL)、trpF和dsbC基因，上游插入了ISAba125元件中的is5。结论：首次报道了BLA(NDM)基因插入不伴随其他耐药基因决定因素的情况。这些观察结果表明，IncX3质粒pNDM-MGR194是BLA(NDM)传播的早期阶段。
Purpose: The aim of the present study was to perform molecular characterisation of the bla(NDM) plasmids and to understand the mechanism of its spread among pathogenic bacteria. Materials and Methods: Seventy-six non-repetitive carbapenem-resistant isolates which were collected during Nov 2011 to April 2013 from four hospitals in Chennai were analyzed for the presence of the bla(NDM) gene by PCR. Further, the genetic context of the bla(NDM) gene was analyzed by PCR specific to ISAba125 and ble(MBL) gene. One of the bla(NDM) plasmid was completely sequenced in the Illumina HiSeq platform. Results: Twenty-three isolates consisting of 8 Escherichia coli, 8 Klebsiella pneumoniae, 3 Klebsiella oxytoca, 3 Acinetobacter baumanii and 1 Pseudomonas aeruginosa were found to carry the bla(NDM) gene. In 18 isolates the bla(NDM) gene was associated with a ble(MBL) gene and the ISAba125 element. The complete sequencing of pNDM-MGR194 revealed an IncX3 replication type plasmid, with a length of 46,253 bp, an average GC content of 47% and 59 putative ORFs. The iteron region contained the bla(NDM5) gene and the ble(MBL), trpF and dsbC genes downstream and an IS5 inserted within the ISAba125 element upstream. Conclusion: This is the first report where the bla(NDM) gene insertion in a plasmid is not accompanied by other resistance gene determinants. These observations suggest that the IncX3 plasmid pNDM-MGR194 is an early stage in the dissemination of the bla(NDM).