Detection of aac(6')-Ib-cr in KPC-producing Klebsiella pneumoniae isolates from Tel Aviv, Israel

J Antimicrob Chemother. 2009 Oct;64(4):718-22. doi: 10.1093/jac/dkp272. Epub 2009 Aug 4.


Objectives: We aimed to evaluate the occurrence and characteristics of plasmid-mediated quinolone resistance (PMQR) genes in KPC-producing (KPC-P) Klebsiella pneumoniae (Kpn) isolates in Tel Aviv Medical Center, Israel.

Methods: Forty-seven KPC-P Kpn isolates were studied. Antibiotic susceptibilities were determined by Vitek 2, Etest or agar dilution. Beta-lactamases and PMQR determinants were detected by PCR. For plasmid characterization, transformation, transconjugation, restriction mapping and Southern blot analysis were performed.

Results: Six out of 47 (13%) KPC-P isolates carried aac(6')-Ib-cr. Acquisition of aac(6')-Ib-cr-encoding plasmids increased the MIC of ciprofloxacin by 2-fold. In five of six KPC-P isolates, aac(6')-Ib-cr and bla(KPC-2) were encoded on the same plasmid.

Conclusions: The most prevalent PMQR gene in the studied KPC-P K. pneumoniae isolates is aac(6')-Ib-cr. The co-existence of PMQR genes with KPC on the same plasmid poses a serious epidemiological, clinical and public-health threat.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases / biosynthesis*
  • Acetyltransferases / genetics
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / biosynthesis*
  • Bacterial Proteins / genetics
  • Blotting, Southern
  • Conjugation, Genetic
  • Drug Resistance, Bacterial*
  • Genes, Bacterial
  • Humans
  • Israel
  • Klebsiella Infections / microbiology*
  • Klebsiella pneumoniae / drug effects*
  • Klebsiella pneumoniae / enzymology
  • Klebsiella pneumoniae / genetics
  • Klebsiella pneumoniae / isolation & purification
  • Microbial Sensitivity Tests / methods
  • Plasmids / analysis
  • Polymerase Chain Reaction / methods
  • Quinolones / pharmacology*
  • Restriction Mapping
  • Transformation, Genetic
  • beta-Lactamases / biosynthesis*
  • beta-Lactamases / genetics


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Quinolones
  • Acetyltransferases
  • aminoglycoside acetyltransferase
  • beta-Lactamases
  • carbapenemase