IncN ST7 epidemic plasmid carrying blaIMP-4 in Enterobacteriaceae isolates with epidemiological links to multiple geographical areas in China

Ya Wang, Wai-U Lo, Raymond Wai-Man Lai, Cindy Wing-Sze Tse, Rodney Allan Lee, Wei-Kwang Luk, Vincent Chi-Chung Cheng, Tak-Lun Que, Kin-Hung Chow, Pak-Leung Ho

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32 Citations (SciVal)


OBJECTIVES: To characterize blaIMP-4-carrying plasmids originating from inpatients in Hong Kong.

METHODS: Sixteen blaIMP-4-carrying plasmids identified among Enterobacteriaceae (nine Escherichia coli, four Klebsiella pneumoniae, two Citrobacter freundii and one Enterobacter cloacae) recovered from 15 patients were characterized. The isolates, collected during January 2010 to December 2013, were retrospectively investigated by plasmid sequencing, molecular and fitness studies.

RESULTS: The blaIMP-4-carrying plasmids belonged to the IncN ST7 lineage (∼50 kb). Twelve of the 16 plasmids were epidemiologically linked to seven different regions in China. Alignment of the complete plasmid sequences showed identical plasmid backbones and two highly similar resistance regions, each carrying one of two resistance genes (blaIMP-4 and qnrS1). The blaIMP-4 was detected in a class 1 integron (containing blaIMP-4 and intron that is part of an IS6100-IS26 transposon-like structure. The nine E. coli carrying the epidemic plasmid belonged to multiple multilocus STs (six ST542, one ST131, one ST657 and one ST3177). Fitness assays performed on E. coli J53 recipients showed that the presence of the epidemic plasmid did not have a significant biological cost.

CONCLUSIONS: This study identified a blaIMP-4-carrying IncN ST7 plasmid disseminated among multiple enterobacterial species originating from patients with epidemiological links to different regions in China.

Original languageEnglish
Pages (from-to)99-103
Number of pages5
JournalThe Journal of Antimicrobial Chemotherapy
Issue number1
Publication statusPublished - Jan 2017

Bibliographical note

© The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: [email protected].


  • Aged
  • Aged, 80 and over
  • Cross Infection/epidemiology
  • Enterobacteriaceae/enzymology
  • Enterobacteriaceae Infections/epidemiology
  • Female
  • Gene Transfer, Horizontal
  • Hong Kong/epidemiology
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Plasmids/analysis
  • Retrospective Studies
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Topography, Medical


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