Synergistic antibacterial activity of mycosynthesized AgNPs with antibiotics against multidrug resistant <em>Pseudomonas aeruginosa</em> and investigation of protein profile

Abstract

Silver nanoparticles (AgNPs) have been identified as promising bactericidal agents especially towards multidrug resistant bacteria (MDR). Fungi are excellent biogenic sources for synthesizing AgNPs with antibacterial activity. In the present study, AgNPs were synthesized using Aspergillus niger extract and characterized. Individual and synergistic antibacterial activities of AgNPs were tested against isolated hospital strain of MDR Pseudomonas aeruginosa by disc diffusion assay. SDS-PAGE analysis was performed to analyse the protein expression before and after treatment with AgNPs. Results revealed the successful synthesis of AgNPs using A. nigerby 24 hrs and the average particle size was measured as 18.72±0.2 nm. AgNPs were predominantly spherical and monodispersed. 18±0.05 mm zone of inhibition was observed for P. aeruginosa when treated with AgNPs alone whereas synergistic treatment of synthesized AgNPs along with Tetracycline showed impressive antibacterial activity (27.32±2 mm). Protein expression of P. aeruginosa varied before and after treatment which was evident from the results. This indicated the effective breakdown of cell wall and cellular proteins on the synergistic treatment of AgNPs and antibiotics. Thus the study demonstrates a feasible and eco-friendly approach to synthesize AgNPs with enhanced antibacterial activity against MDR bacterial strains.