Abstract:

Purpose: To carry out eco-friendly biosynthesis of fungi-derived silver nanoparticles (AgNPs) andinvestigate their antibacterial synergies with essential oils (EOs) of Asteriscus graveolens (Forssk.)Less. and Cupressus sempervirens.Methods: Biosynthesis of AgNPs was carried out using a cell-free filtrate of Tritirachium oryzae. Thebiosynthesized AgNPs characteristics were assessed using different methods, including ultravioletvisiblespectrophotometry (UV), Fourier-transform infrared spectroscopy (FTIR), scanning electronmicroscopy (SEM) with energy-dispersive x-ray spectroscopy (EDS) and transmission electronmicroscopy (TEM).Results: Obvious synergistic effects were observed between AgNPs and chloramphenicol, vancomycin,nitrofurantoin or tetracycline with Pseudomonas aeruginosa, through increases in fold area of inhibition(IFAs) within the range of 2.4 to 9.0. Synergistic interactions were also seen between AgNPs and theantibiotics used, depending on the strain. Increase in IFA ranged from 1- to 3-fold for S. aureus, E. coliand P. aeruginosa. Similarly, combinations of AgNPs, EO of A. graveolens and cefotaxime,nitrofurantoin or amoxicillin against P. aeruginosa led to 10-, 3- and 10-fold synergy, respectively. Incontrast, the use of AgNPs and trimethoprim, tetracycline or amoxicillin against E. coli led to 1 to 6-foldsynergy. The best synergistic capacity resulted from AgNPs and the EO of C. sempervirens andtrimethoprim against S. epidermidis, which yielded 29-fold increase in IFA. The use of combination ofAgNPs and vancomycin against P. aeruginosa led to 16.4-fold enhancement of IFA.Conclusion: The findings can potentially lead to the development of a new perception of antibacterialagents (innovative medications) involving the incorporation of nanoparticles (NPs) or new materials thatpotentially synergize with antibiotics, NPs and the EOs of different plants.