Eastern Lubber Grasshopper Extract-Inspired Silver Nanoparticles Selectively Inhibit Methicillin-Resistant Staphylococcus aureus

Silver nanoparticles (AgNPs) were synthesized using a protein/polypeptide-rich aqueous extract from the Eastern lubber grasshopper (Romalea microptera), as a natural reducing and capping agent. The resulting AgNPs exhibited relatively uniform sizes (10–60 nm) and were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-visible (UV-Vis) spectroscopy, Transmission electron microscopy (TEM), and Scanning Electron Microscopy (SEM). Disk diffusion tests against five bacterial strains (Methicillin-resistant Staphylococcus aureus (MRSA), Burkholderia cenocepacia, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli) demonstrated that the insect-extract-induced AgNPs selectively and significantly inhibited MRSA growth, with an average value of zone of inhibition of 9.16 ± 1.11 mm (n = 4). Statistical analysis confirmed the superior antibacterial activity of the Eastern lubber grasshopper-derived AgNPs against MRSA compared to citrate-capped AgNPs and free silver ions. These findings reveal the potential of insect-derived AgNPs as selective, green-synthesized antibacterial agents with enhanced efficacy and reduced side effects, particularly against antibiotic-resistant pathogens.