Efflux Pump Inhibitor Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP) Effect on the Minimum Inhibitory Concentration of Ciprofloxacin in Acinetobacter baumannii Strains

One of the most important pathogens with increasing mortality rate in hospitalized patients is Acinetobacter baumannii.
Therefore, this study aimed at detecting multidrug-resistance and the role of efflux pumps in Ciprofloxacin resistance of A. baumannii strains isolated from burn patients.
Eighty A. baumannii strains collected from 240 wound samples were isolated from burn patients hospitalized in the burn unit of Shahid Motahari hospital. Susceptibility to antibiotics was tested by disc diffusion and microdilution methods. Activity of the efflux pump system was assessed using the efflux pump inhibitor, Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP). Polymerase Chain Reaction (PCR) and sequencing were done for detecting the AdeABC genes.
Overall, 100% of A. baumannii isolates were resistant to ceftriaxone, ceftazidime, cefepime, cefotaxime, meropenem, ciprofloxacin, co-trimoxazole, piperacilin, piperacillin/tazobactam and imipenem; 72 (90%) to amikacin, 72 (90%) to gentamicin, and 0 (0.0%) to colistin The high increase of the susceptibility to ciprofloxacine in the strains in the presence of the efflux pump inhibitor was remarkable. In 25% of isolates, CCCP decreased the minimum inhibitory concentrations (MIC) by 4 to 64 folds. In 80 (100%) of the isolates, adeb, adeA, and adeC genes were detected.
The results indicated the role of efflux pump in antibiotic resistance in A. baumannii isolates. Furthermore, A. baumannii strains could resist antibiotics by the efflux mechanism.