Shahrekord University of Medical Sciences Journal of Herbmed Pharmacology 2345-5004 11 3 2022 07 01 Antibacterial activity of airborne fungal mediated nanoparticles in combination with Foeniculum vulgare essential oil 419 427 10.34172/jhp.2022.48 EN Haitham Qaralleh https://orcid.org/0000-0002-9658-0040 Khaled Khleifat https://orcid.org/0000-0002-0216-3175 Muhamad Al-Limoun https://orcid.org/0000-0003-3015-7562 Amjed Al-Tarawneh https://orcid.org/0000-0003-3701-8717 Waqar Khleifat https://orcid.org/0000-0002-4700-2156 Ibrahem Almajali https://orcid.org/0000-0003-0123-0150 Rula Buqain https://orcid.org/0000-0002-1134-0903 Khalid A. Shadid https://orcid.org/0000-0002-8484-0546 Noorah Aslowayeh https://orcid.org/0000-0003-0203-9921 Journal Article 10.34172/jhp.2022.48 2022 03 17 2022 05 06 Introduction: A cost-effective and ecologically friendly method of generating silver nanoparticles (AgNPs) includes pathways that utilize a variety of biological sources to decrease metal ions. This study was designed to synthesize AgNPs using a fungus strain Aspergillus flavus and evaluate its antibacterial activities alone or in combination with Foeniculum vulgare (fennel) essential oil (EO). Methods: The antibacterial activity of different concentrations of biosynthesized AgNPs by Aspergillus flavus individually and in combination with fennel EO was investigated using disc diffusion methods and minimal inhibitory concentration (MIC). Bacterial species, including Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterobacter cloacae, Shigella sp., Staphylococcus aureus, and Staphylococcus epidermidis were tested. Results: Formation of dark brown color, ultraviolet-visible (UV/Vis) spectroscopy, transmission electron microscope (TEM), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were used for the characterization of AgNPs. Obvious synergistic effects were observed between AgNPs and EO of fennel (F. vulgare) with all tested bacteria except S. aureus, through increases in fold area of inhibition (IFAs) within the range of 0.15 to 8.87. Although S. aureus had the most susceptibility toward both AgNPs and EO of fennel (24 and 17 mm, respectively), no synergistic activity was exhibited. The best synergistic capacity resulted from AgNPs and fennel EO was observed against S. epidermidis (8.87-fold in IFA). Conclusion: This study revealed that when biosynthesized AgNPs were mixed with the EO of F. vulgare, they became more bacteriostatic and might be developed to treat bacterial infections in the future.