肺炎克雷伯菌中新的质粒介导的黏菌素耐药基因 mcr-7.1。
Novel plasmid-mediated colistin resistance gene mcr-7.1 in Klebsiella pneumoniae.
机构信息
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Science, Sichuan University, Chengdu, China.
Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Chengdu, China.
出版信息
J Antimicrob Chemother. 2018 Jul 1;73(7):1791-1795. doi: 10.1093/jac/dky111.
OBJECTIVES
To identify a novel plasmid-mediated colistin resistance gene in Klebsiella pneumoniae isolated from chickens in China.
METHODS
WGS was used to identify a novel colistin resistance gene. The transferability of plasmids carrying mcr-7.1 was investigated by conjugation experiments. The expression of the mcr-7.1 gene was examined using an expression vector.
RESULTS
A novel plasmid-mediated colistin resistance gene mcr-7.1, sharing 70% amino acid identity with the mcr-3 gene, was identified in three K. pneumoniae strains isolated from chickens in China. The mcr-7.1 gene was found in an IncI2-type plasmid (pSC20141012) that co-harboured the blaCTX-M-55 gene in one isolate. pSC20141012 can be transferred from K. pneumoniae SC20141012 to Escherichia coli J53Azr, exhibiting a ≥8-fold increase in colistin MIC compared with the recipient E. coli J53Azr.
CONCLUSIONS
We identified a novel plasmid-mediated colistin resistance gene named mcr-7.1 in K. pneumoniae in China. The prevalence of mcr-7.1 in various species of human and animal origin needs to be investigated immediately.
目的
在中国鸡源肺炎克雷伯菌中鉴定一种新型质粒介导的黏菌素耐药基因。
方法
使用 WGS 鉴定一种新型黏菌素耐药基因。通过接合实验研究携带 mcr-7.1 的质粒的可转移性。使用表达载体检测 mcr-7.1 基因的表达。
结果
在中国鸡源肺炎克雷伯菌的 3 株分离株中发现了一种新型的质粒介导的黏菌素耐药基因 mcr-7.1，其与 mcr-3 基因的氨基酸序列相似度为 70%。mcr-7.1 基因位于 IncI2 型质粒（pSC20141012）中，该质粒与一株分离株中的 blaCTX-M-55 基因共存。pSC20141012 可从肺炎克雷伯菌 SC20141012 转移到大肠杆菌 J53Azr，与受体大肠杆菌 J53Azr 相比，黏菌素 MIC 增加了 8 倍以上。
结论
我们在中国肺炎克雷伯菌中鉴定出一种新型的质粒介导的黏菌素耐药基因 mcr-7.1。需要立即调查 mcr-7.1 在各种人类和动物来源物种中的流行情况。
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