Volume 43, Issue 3 (10-2019)                   Research in Medicine 2019, 43(3): 118-123 | Back to browse issues page

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, dr_kumarss_amini@yahoo.com
Abstract:   (3586 Views)
Background: Pseudomonas aeruginosa (P. aeruginosa), a common cause of nosocomial infections,
has an intrinsic resistance to many antibiotics. Among all the multidrug efflux pumps involved in
P. aeruginosa drug resistance, MexAB-OprM is the first efflux pump detected to target different
classes of antibiotics. The present study aimed to determine the antibacterial effect of iron oxide
nanoparticles (IONPs) and probiotic bifidobacterium bifidum (BB) on MexA gene expression, as an
important component of the MexAB-OprM multidrug efflux system, in P. aeruginosa isolates of the
patients referred to major hospitals in Tehran, between 2018-2017.
Materials and Methods: In the present descriptive cross-sectional study, a total of 60 isolates
of P. aeruginosa were isolated from patients admitted to major hospitals of Tehran, Iran. After
bacterial identification via biochemical tests, all strains were evaluated for the presence of MexA
of MexAB-OprM multidrug efflux pump in P. aeruginosa using PCR method. After treatment, broth
microdilution method and Real-time PCR were used to assess the antimicrobial activity of IONPs
and probiotic BB and the gene expression level of MexA component, respectively. Changes in MexA
gene expression were analyzed using the -2 ΔΔCT method and independent t-test.
Results: In the present study, 10 isolates (%16.6) of P. aeruginosa harbored MexA gene. The result
of MIC testing and gene expression assay showed that IONPs and probiotic BB did not exhibit any
inhibitory activity against clinical isolates of P. aeruginosa and no change was observed in MexA
gene expression.
Conclusion: Considering the chromosomally encoded MexA, it can be used as markers for
identification of drug resistance of P. aeruginosa as essential elements of an effective infection control
program. In the view of the inhibitory activity of IONPs and probiotic Bifidobacterium bifidium on
bacterial growth and the low inhibitory effect of the elements on activity of the MexAb-OprM efflux
pump, the study of other contributing factors for the development of multi-drug resistance phenotype,
including various other efflux pumps and mechanisms influencing maintenance of resistance should
not be ignored.
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Type of Study: Original | Subject: Microbiology
Received: 2018/12/26 | Accepted: 2019/06/3 | Published: 2019/09/17

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