Mutant prevention concentrations of ciprofloxacin against urinary isolates of Escherichia coli and Klebsiella pneumoniae

  • Ziad Daoud University of Balamand, Tripoli, Lebanon
  • Elie Salem Sokhn University of Surrey, Guildford, United Kingdom
  • Eid Azar University of Balamand, Tripoli, Lebanon
  • Khalil Masri Centre Hospitalier du Nord, Zgharta, Lebanon
  • Shira Doron Tufts Medical Center, Boston, MA,United States
Keywords: mutant prevention concentration, ESBL, ciprofloxacin, Escherichia coli, Klebsiella pneumoniae

Abstract

Introduction: The aim of this work was to study the ability of ciprofloxacin to restrict the development of resistant mutants of Escherichia coli and Klebsiella pneumoniae through determination of the Mutant Prevention Concentration (MPC).

Methodology: We studied 140 strains of E. coli and 86 strains of K. pneumoniae with different profiles of sensitivity to fluoroquinolones and extended spectrum beta lactamase (ESBL) production. The MPCs were determined using an inoculum of 1010 CFU/ml in Mueller-Hinton agar plates with serial concentrations of ciprofloxacin.

Results: Ciprofloxacin-susceptible ESBL-producing strains showed a higher MPC for ciprofloxacin (P <0.001) than ciprofloxacin-susceptible non ESBL-producing strains, while ciprofloxacin-resistant ESBL-producing and non ESBL-producing strains did not significantly differ. The presence of qnr variants was associated with elevated MPCs. This was observed for both tested organisms.

Conclusions: Our study helps to explain the frequent finding of resistance to fluoroquinolones in ESBL-producing strains. Consequently, the use of concentrations of ciprofloxacin higher than the MIC in order to prevent the recovery and growth of resistant mutants is recommended.

Author Biography

Ziad Daoud, University of Balamand, Tripoli, Lebanon

Professor of Clinical Microbiology

Department of Biomedical Sciences

Microbiology

Published
2014-02-13
How to Cite
1.
Daoud Z, Sokhn ES, Azar E, Masri K, Doron S (2014) Mutant prevention concentrations of ciprofloxacin against urinary isolates of Escherichia coli and Klebsiella pneumoniae. J Infect Dev Ctries 8:154-159. doi: 10.3855/jidc.3164
Section
Original Articles