Association Between Drug Efflux Pumps and Resistance to Ciprofloxacin in Clinical Isolates of Acinetobacter baumannii

Background and Aim: Acinetobacter baumannii (A. baumannii) is an important bacterium that can cause multidrug-resistant nosocomial infections in the patients who are admitted to different hospital wards. Various factors play role in the resistance of this bacterium to antibiotics, one of the most important of which is the presence of drug efflux pumps. This study aimed to investigate the presence of the AdeABC efflux system and its role in drug resistance by inactivating them. Materials and Methods: Clinical samples were collected from three hospitals in Tehran, Iran for one year. The initial diagnosis and identification of A. baumannii was done by culture and biochemical methods. Finally, the identified prototypes were confirmed by molecular method. To investigate the role of antibiotic efflux pump in the drug resistance, minimum inhibitory concentration (MIC) for ciprofloxacin in the presence and absence of an efflux pump inhibitor, carbonyl cyanide 3-chlorophenylhy­drazone (CCCP), was determined by microdilution method. Additionally, the presence of adeB, adeR, and adeS genes related to the AdeABC depletion system was investigated by PCR. Results: The results showed that more than 98% of the isolated bacteria had adeB, adeR, and adeS genes in the AdeABC depletion system. Approximately, 47.18% of these bacteria displayed a fourfold reduction in ciprofloxacin MIC levels in the presence of CCCP. Conclusion: Administration of a suitable antibiotic along with a safe efflux pump inhibitor for the treatment of A. baumannii infections can help to reduce the material and spiritual damages caused by the resistant bacteria.