Epidemiological characteristics and genetic structure of blaNDM-1 in non-baumannii Acinetobacter spp. in China

J Antimicrob Chemother. 2012 Sep;67(9):2114-22. doi: 10.1093/jac/dks192. Epub 2012 May 17.


Objectives: The goal of this study was to investigate the epidemiological characteristics and the surrounding genetic structure of bla(NDM-1) in non-baumannii Acinetobacter spp. in China.

Methods: Non-baumannii Acinetobacter spp. were collected from 28 provinces in China and were screened for the presence of bla(NDM-1) using PCR. The following four methods were used to classify the Acinetobacter isolates: the Vitek 2 system, 16S-23S rRNA gene intergenic spacer sequencing, amplified rDNA restriction analysis and partial rpoB sequence analysis. An S1-PFGE assay and Southern blot hybridization were performed to determine the plasmid location of bla(NDM-1). The transferability of bla(NDM-1)-harbouring plasmids was confirmed by conjugation experiments and electrotransformation. The surrounding genetic structure of the bla(NDM-1) gene was analysed using a restriction endonuclease-based cloning approach and primer walking.

Results: Among 726 non-baumannii Acinetobacter spp., nine isolates collected from six different provinces and assigned to seven different Acinetobacter spp. contained the bla(NDM-1) gene. None of these isolates was directly infectious to the patients or demonstrated an epidemiological importation from abroad. These bla(NDM-1) genes were located on plasmids that could be transferred to Escherichia coli J53 by conjugation and Acinetobacter baylyi ADP1 by electrotransformation. Seven of the nine strains shared a common genetic structure in which bla(NDM-1) was flanked by two copies of ISAba125.

Conclusions: The clinical challenge posed by bla(NDM-1) is currently minimal in China; however, more attention should be devoted to monitoring the dissemination of this gene due to its potential transferability via the ISAba125-associated transposon.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter / drug effects*
  • Acinetobacter / enzymology*
  • Acinetobacter / genetics
  • Acinetobacter / isolation & purification
  • Acinetobacter Infections / epidemiology*
  • Acinetobacter Infections / microbiology*
  • Adult
  • Aged
  • Bacterial Typing Techniques
  • Blotting, Southern
  • Child
  • China
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • DNA, Bacterial / metabolism
  • DNA, Ribosomal / chemistry
  • DNA, Ribosomal / genetics
  • Electrophoresis, Gel, Pulsed-Field
  • Female
  • Humans
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Molecular Typing
  • Polymerase Chain Reaction
  • RNA, Ribosomal, 16S / genetics
  • Restriction Mapping
  • Sequence Analysis, DNA
  • beta-Lactamases / genetics*
  • beta-Lactamases / metabolism*


  • DNA, Bacterial
  • DNA, Ribosomal
  • RNA, Ribosomal, 16S
  • beta-Lactamases
  • beta-lactamase NDM-1

Associated data

  • GENBANK/JQ080305
  • GENBANK/JQ739157
  • GENBANK/JQ739158
  • RefSeq/NC_019322
  • RefSeq/NC_019323