Comparative genomics of rmtB-carrying IncI1 ST136 plasmids in avian escherichia coli isolates from chickens in China
Comparative genomics of rmtB-carrying IncI1 ST136 plasmids in avian escherichia coli isolates from chickens in China
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中国鸡禽大肠杆菌中携带 rmtB 的 IncI1 ST136 质粒的比较基因组学
DOI：
10.1016/j.ijantimicag.2017.12.009
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发表时间：
2018
影响因子：
10.8
通讯作者：
Pan YS
中科院分区：
文献类型：
--
作者：
Yuan Li;Liu Jian-Hua;Du Xiang-Dang;Chen Min;Hu Gong-Zheng;Pan Yu-Shan;Zong Zhi-Yong;Pan YS
我们在之前的研究中鉴定了来自中国一个农场的8株携带mtb的航空大肠杆菌，但对这些质粒的骨干和整个多耐药区（MRRs）知之甚少。本研究采用全质粒测序对三个携带mtb的ince1 ST136质粒进行了分析和比较。这些质粒由一个83 470 bp的IncI1主干组成，该主干携带负责质粒复制、转移、维持和稳定功能的基因，pEC006和pEC007的MRR为17 330 bp， pEC008的MRR为34 626 bp。质粒pEC006是不可转移的，因此该基因的截断可能解释了无法结合。pEC008包含blatem1，rmtB,aacC2,tetA，floRandstrABgenes以及1类整合子盒阵列（|dfrA12|或ff |aadA2|），其中散布着不同的可移动元件，包括Tn2， Tn1721, Tn1722, Tn5393, ISCfr1, IS5057， iscr1和ISCR2，以及IS26的三个拷贝。pEC008的MRR可能是由tn1722转位到质粒主干引起的。mrr的获取和重排表明了不同抗性决定因素的积累。
EightrmtB-carrying avianEscherichia colistrains from a farm in China were characterised in our previous study, but little is known about the backbones and entire multiresistance regions (MRRs) of these plasmids. Here, threermtB-carrying IncI1 ST136 plasmids were analysed by whole-plasmid sequencing and were compared. These plasmids were composed of an 83 470-bp IncI1 backbone carrying genes responsible for plasmid replication, transfer, maintenance and stability functions, as well as a 17 330-bp MRR for pEC006 and pEC007, and a 34 626-bp MRR for pEC008. Plasmid pEC006 was not transferable, thus truncation of thetraIgene may explain the inability to conjugate. pEC008 harboured theblaTEM-1,rmtB,aacC2,tetA,floRandstrABgenes as well as a class 1 integron cassette array (|dfrA12|orfF|aadA2|), which were interspersed with different mobile elements, including Tn2, Tn1721, Tn1722, Tn5393, ISCfr1, IS5057, ISCR1and ISCR2, and three copies of IS26. The MRR of pEC008 may have resulted from transposition of Tn1722into the plasmid backbone. Acquisition and rearrangement of MRRs demonstrated the accumulation of different resistance determinants.