Plasmid-mediated quinolone resistance in Aeromonas allosaccharophila recovered from a Swiss lake

J Antimicrob Chemother. 2008 Nov;62(5):948-50. doi: 10.1093/jac/dkn341. Epub 2008 Sep 3.


Objectives: To search for plasmid-mediated qnr genes among waterborne environmental Aeromonas spp. recovered from Switzerland.

Methods: Isolates presenting MICs of nalidixic acid or ciprofloxacin > or = 1 mg/L were screened for qnr genes by a multiplex PCR approach followed by sequencing. Plasmids were transferred by transformation, and further analysis of the genetic structures surrounding the qnrS2 gene was carried out by PCR and sequencing.

Results: A qnrS2 gene was identified from a single Aeromonas allosaccharophila isolate (Lugano lake, Lugano), as part of a mobile insertion cassette located on a broad host range IncU-type plasmid. This plasmid co-harboured a class 1 integron containing the aac(6')-Ib-cr, bla(OXA-1), catB3 and arr-3 gene cassettes.

Conclusions: These findings strengthen further the role of Aeromonas spp. as a reservoir of antimicrobial resistance determinants in the environment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aeromonas / drug effects*
  • Aeromonas / isolation & purification
  • Anti-Bacterial Agents / pharmacology*
  • DNA, Bacterial / genetics
  • Drug Resistance, Bacterial*
  • Fresh Water / microbiology*
  • Gene Order
  • Genes, Bacterial
  • Integrons
  • Interspersed Repetitive Sequences
  • Microbial Sensitivity Tests
  • Plasmids
  • Polymerase Chain Reaction
  • Quinolones / pharmacology*
  • Sequence Analysis, DNA
  • Switzerland


  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Quinolones