Green synthesis of silver nanoparticle using Acroptilon repens extract and evaluation of its anti-efflux activity against Acinetobacter bumanni clinical isolates

Efflux pumps are one of the mechanisms for antibiotic resistance in Acinetobacter baumannii isolates. The aim of the present study was to investigate the green synthesis of silver nanoparticles using Acroptilon repens extract and evaluation of its anti- efflux activity in antibiotic-resistant A. baumannii isolates.
In this experimental study, the silver nanoparticles were synthesized using A. repens alcoholic extract and the structure of the synthesized silver nanoparticles was confirmed by spectrophotometry (UV-Vis), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Subsequently, the adeAC efflux pump was detected in 21 A. baumannii clinical isolates using Cartwheel and Polymerase Chain Reaction (PCR) methods. Finally, the anti-efflux pump activity of silver nanoparticles was evaluated by Minimum Inhibition Concentration (MIC) technique.
The synthesized silver nanoparticle was confirmed by maximum absorbance at 420 nm wavelength, using UV-Vis method. The SEM and TEM micrographs showed that nanoparticles are spherical and have an average size of 38.89 nm. Moreover, the XRD results confirmed the cubic structure of silver nanoparticles. The results of Cartwheel and PCR methods revealed that the 12 out of 21 isolates have active efflux pumps. Furthermore, the MIC of ethidium bromide in resistant strains with silver nanoparticles was decreased.
Based on anti-efflux pump activity of silver nanoparticles against A. bumannii strains, it seems that silver nanoparticles have potential uses for pharmaceutical industries, though further studies are required to confirm the results of this study.