Molecular analysis of NDM-1-producing enterobacterial isolates from Geneva, Switzerland

J Antimicrob Chemother. 2011 Aug;66(8):1730-3. doi: 10.1093/jac/dkr174. Epub 2011 May 31.

Abstract

Objectives: To analyse the mechanisms responsible for decreased susceptibility or resistance to carbapenems in several enterobacterial isolates recovered in 2009-10 in Geneva University Hospitals, Switzerland.

Methods: PCR and sequencing were used to identify β-lactamases, 16S RNA methylases and plasmid-mediated quinolone resistance genes. The transferable properties of the plasmids were analysed, as well as their plasmid type. The strains were typed by multilocus sequence typing.

Results: Three patients were found to be positive for NDM-1-producing enterobacterial isolates (one with Escherichia coli and Klebsiella pneumoniae, one with K. pneumoniae only and one with Proteus mirabilis), where NDM-1 stands for New Delhi metallo-β-lactamase-1. The bla(NDM-1) carbapenemase gene was detected in all isolates in addition to genes encoding narrow-spectrum β-lactamases (TEM-1, SHV-11, OXA-1, OXA-9 and OXA-10), extended-spectrum β-lactamases (CTX-M-15, CMY-16 and CMY-30), ArmA and quinolone resistance determinants (Qnr). The bla(NDM-1) gene was located on conjugative IncA/C- or IncF-type plasmids. Upstream of the bla(NDM-1) gene, part of ISAba125, previously identified in NDM-1-negative Acinetobacter baumannii, was found. Downstream of the bla(NDM-1) gene, variable sequences were found.

Conclusions: This work constitutes the first identification of NDM-1 producers in Switzerland. Interestingly, patients from whom these NDM-1-producing isolates were recovered had a link with the Indian subcontinent or the Balkans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Carbapenems / pharmacology
  • Conjugation, Genetic
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • Enterobacteriaceae / classification
  • Enterobacteriaceae / drug effects
  • Enterobacteriaceae / enzymology*
  • Enterobacteriaceae / genetics*
  • Enterobacteriaceae Infections / epidemiology*
  • Enterobacteriaceae Infections / microbiology*
  • Gene Transfer, Horizontal
  • Hospitals, University
  • Humans
  • Multilocus Sequence Typing
  • Plasmids / analysis
  • Polymerase Chain Reaction
  • Quinolones / pharmacology
  • Sequence Analysis, DNA
  • Switzerland / epidemiology
  • beta-Lactam Resistance*
  • beta-Lactamases / genetics*
  • tRNA Methyltransferases / genetics

Substances

  • Anti-Bacterial Agents
  • Carbapenems
  • DNA, Bacterial
  • Quinolones
  • tRNA Methyltransferases
  • beta-Lactamases
  • beta-lactamase NDM-1