Novel plasmid-mediated colistin resistance gene mcr-7.1 in Klebsiella pneumoniae

• Published in: Journal of antimicrobial chemotherapy Vol. 73; no. 7; pp. 1791 - 1795
• Main Authors: Yang, Yong-Qiang, Li, Yun-Xia, Lei, Chang-Wei, Zhang, An-Yun, Wang, Hong-Ning
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.07.2018
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/dky111

Abstract 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.