Involvement of AcrAB and OqxAB Efflux Pumps in Antimicrobial Resistance of Clinical Isolates of Klebsiella pneumonia

Document Type : Original Article


1 Department of Microbiology, Faculty of Sciences, Karaj Branch, Islamic Azad University, Karaj, Iran

2 Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran


Introduction: Infections caused by multidrug-resistant Klebsiella pneumonia characterize a major warning throughout the world owing to enhanced mortality and treatment limitations. Efflux pumps have an important role as a mechanism of antibiotic resistance in K. pneumoniae. In the current study, the role of AcrAB and OqxAB efflux pumps to antibiotic resistance was investigated in clinical isolates of K. pneumonia.
Materials and Methods: During August 2017-October 2018, 110 clinical strains of K. pneumoniae were obtained from patients referred to the hospitals in Tehran. After microbiological/biochemical identification, and antimicrobial susceptibility test was performed using the disc diffusion method. Then, the minimum inhibitory concentration of ciprofloxacin-resistant K. pneumoniae strains was measured by the broth microdilution method. For investigating the efflux pump mediated drug resistance in K. pneumoniae, the presence, and prevalence of efflux genes (acrA/acrB and oqxA/oqxB) were examined by the Polymerase Chain Reaction (PCR) technique.
Results: The results showed that resistance to ciprofloxacin, norfloxacin, gentamicin, kanamycin, cefotaxime, trimethoprim, chloramphenicol, and colistin was 19.09%, 21.81%, 10.0%, 9.09%, 44.54%, 25.45%, 11.81%, and 61.81%, respectively, in K. pneumoniae clinical isolates. The PCR technique demonstrated that the prevalence of acrA/acrB and oqxA/oqxB genes are 58 (52.72%) and 52 (47.27%), respectively.
Conclusions: The results of this study reveal that the AcrAB and OqxAB efflux pumps have a major role in the antibiotic resistance of multidrug resistance K. pneumoniae isolates. Therefore, due to the easy transfer of antimicrobial resistance genes, the accurate detection of resistance genes by molecular methods is essential to control the spread of resistant strains.