Role of Efflux Pump Gene adeIJK to Multidrug Resistance in Acinetobacter baumannii Clinical Isolates

Background: The emergence of multidrug-resistant Acinetobacter baumannii (MDRAB) as a nosocomial pathogen is one of the major public health problems. This study aimed to evaluate the role of an efflux pump gene adeJ for the multidrug resistance of A. baumannii clinical isolates. Methods: Two groups, MDRAB and susceptible A. baumannii (SAB), of baumannii clinical isolates were studied. The SAB group consisted of strains that did not meet the criteria of MDRAB and were susceptible to more categories of antibiotics than MDRAB. Antimicrobial susceptibility results obtained by the VITEKⅡ system were used in data analysis and bacterial group allocation. We performed real-time reverse transcription PCR to determine the relative expression of adeJ. We compared the relative expression of adeJ in comparison groups by considering two viewpoints: (1) MDRAB and SAB groups,and (2) susceptible and non-susceptible groups for each antibiotic used in this study.Results: The mean value of relative expression of adeJ of MDRAB and SAB groups was 1.4 and 0.92, respectively, and showed significant differences (P = 0.002). The mean values of relative expression of adeJ of susceptible and non-susceptible groups to the antibiotics cefepime, ceftazidime, ciprofloxacin, imipenem, meropenem, tigecycline, piperacillin/tazobactam, ticarcillin/clavulanic acid, trimethoprim/sulfamethoxazole, piperacillin, and gentamicin showed statistically significant differences (P < 0.05). Conclusion: The overexpression of adeIJK might contribute to the multi-drug resistance in A. baumannii clinical isolates. Further, the overexpression of adeIJK might be one of the factors contributing to the resistance to numerous antibiotics.