Multi-drug Resistance Profiles and Expression of AdeIJK and AbeM in Acinetobacter baumannii Collected from Humans by Real-time PCR

Acquiring genetic determinants with antibiotic resistance and mutation in regulatory genes of Acinetobacter baumannii can made many problems in treatment of patients. The AdeIJK pump are associated with decrease susceptibility to trimethoprim, fluoroquinolones, β-lactams, novobiocin, tetracycline, lincosamides, erythromycin, chloramphenicol and AbeM pump can decrease the MIC of chloramphenicol, trimethoprim, aminoglycosides and fluoroquinolones. Upregulation of drug transporters systems, modifications in gyrA and parC genes have major role to fluoroquinolones resistance in A. baumannii. The aim of this study was investigation the contribution of adeJ and abeM pumps in extrusion of ciprofloxacin in A. baumannii.
For confirmation of species the blaOXA-51 gene was applied. Disk diffusion method was performed for antimicrobial susceptibility test. For illustration of active efflux pumps the CCCP and ciprofloxacin were used to determine MIC. To detect the RNA transcript of AdeJ and AbeM pumps in isolates collected from two hospitals from July 2016 to March 2017 qRT-PCR was carried out.
The MICs of ciprofloxacin decreased 32-fold or more in 7 strains, 16-fold in 2 strains, 8-fold in 10 strains, 4-fold in 25 strains and 2-fold in 6 strains after adding CCCP. Overexpression of the adeJ (84%) and abeM (88.63%) genes were indicated by qRT-PCR.
Efflux pups inhibitor are new approach for increase susceptibility to many classes of antibiotics. In A. baumannii strains transporting system may have contribution in ciprofloxacin resistance as shown with this study.