Background: A. baumannii constitutes a major public health problem due to its propensity to develop resistance to numerous drugs and isolates exhibiting multidrug resistance are emerging in clinical settings. The aim of this study is to evaluate the role of efflux pump gene adeJ for the multidrug resistance of A. baumannii clinical isolates.
Materials and methods: Two reference strains of A. baumannii and 100 clinical isolates including 70 multidrug-resistant A. baumannii and 30 non-multidrug-resistant A. baumannii were used in this study. Antimicrobial susceptibility results obtained by VITEKⅡ system were used in data analysis and bacterial group allocation. We performed real-time reverse transcription PCR assay to determine relative expression of adeJ gene.
We compared relative expression of adeJ efflux pump gene in comparison groups according to two viewpoint: i) multidrug-resistant A. baumannii and non- multidrug-resistant A. baumannii group and ii) susceptible and non-susceptible group for various antibiotics.
Results: The mean value of relative expression of adeJ gene of multidrug resistant A. baumannii and non multidrug resistant A. baumannii group determined by real-time reverse transcription PCR were 0.92 and 1.4, respectively. The difference of them was statistically significant. The mean values of relative expression of adeJ gene of susceptible and non-susceptible group for most tested antibiotics including cefepime, ceftazidime, ciprofloxacin, imipenem, meropenem, tigecycline, piperacillin/tazobactam, ticarcillin/clavulanic acid, trimethoprim/sulfamethoxazole, piperacillin and gentamicin showed statistically significant differences.
Conclusion: Because relative expression of adeJ gene of MDRAB and non-MDRAB group of A. baumannii clinical isolates showed significant difference, AdeIJK efflux pump may contribute to the multi-drug resistance of A. baumannii. It seems to be that overexpression of adeIJK gene may contribute the resistance to various antibiotics including cefepime, ceftazidime, cefotaxime, ciprofloxacin, imipenem, meropenem, tigecycline, piperacillin/tazobactam, ticarcillin/clavulanic acid, piperacillin, trimethoprim/sulfamethoxazole and gentamicin.