Minimum Inhibitory Concentration of Ciprofloxacin against Pseudomonas Aeruginosa in the Presence of the Efflux Inhibitor Phenylalanine-arginine Beta-naphthylamide

Abstract

Introduction: Pseudomonas aeruginosa is a gram-negative, opportunistic pathogen causing infections in patients staying in the hospital and is resistant to multiple drugs. This study investigated the resistance to ciprofloxacin by the efflux system of Pseudomonas aeruginosa.Materials and Methods: For this purpose, the inhibitor of the efflux system phenylalanine-arginine beta-naphthylamide was used. In this study, 135 isolates of Pseudomonas aeruginosa were collected from the hospitalized patients of Imam Khomeini Hospital and outpatient clinics in Urmia during a ten-month period from June 2015 to March 2016. These isolates were re-identified by standard microbiological and biochemical methods. Finally, 51 isolates were selected for antibiotic susceptibility testing.Results: According to the antibiogram test, the Pseudomonas aeruginosa isolates exhibited highest resistance against ciprofloxacin (90.2%), tobramycin (88.2%), and gentamycin (86.3%) and the highest sensitivity towards colistin (76.4%), and imipenem (72.5%). The 51 isolates, which were selected for the minimum inhibitory concentration test, had multi-drug resistance regulators.Conclusion: The discovery and development of the efflux system inhibitors is an important strategy to deal with bacterial infections.