Background and Objective: One of the mechanisms involved in the resistance of Klebsiella pneumoniae to fluoroquinolones is AcrAB leakage pumps.  In this study, the prevalence of Klebsiella pneumoniae isolates with AcrAB encoding genes and the role of permeation pumps in fluoroquinolone resistance were investigated.
Materials and Methods: 165 samples from patients of Kermanshah Medical Centers were collected and 100 isolates of Klebsiella pneumoniae approved by API-20E kit. Antibiotic susceptibility of isolates to ciprofloxacin and levofloxacin was determined using disk diffusion and MIC (Minimum Inhibitory Concentration) experiments. AcrA and AcrB genes were determined by PCR method. The effect of bacterial permeation inhibitor (CCCP) Carbonyl cyanide m-chlorophynyl hydrazone with final concentration of 5μg / ml on MIC of fluoroquinolones resistant isolates was done using agar dilution method.
Results: Of the100 Klebsiella pneumoniae isolates, 28 (28%), were resistant to ciprofloxacin and levofloxacin. Both acrA and acrB genes were resistant to antibiotics in all Klebsiella pneumoniae isolates. The effect of CCCP on isolates resistant to ciprofloxacin and levofloxacin resulted in a decrease in MIC in 11 isolates (39.2%), among which the MIC was changed in five isolated from resistant to susceptible state.
Conclusion: Although the high drug resistance of isolates is not due to permeation pumps, the results of inhibition of pump indicate their role in the resistance of 39% of isolates. Also, the presence of AcrAB genes in all fluoroquinolones resistant Klebsiella pneumoniae isolates shows the importance of these pumps.