Eco-friendly biosynthesis of silver nanoparticles by saprophytic Fusarium solani as a sustainable therapeutic approach for the management of methicillin-resistant Staphylococcus aureus wound infections

The rising prevalence of antimicrobial resistance (AMR) has prompted the exploration of novel, naturally sourced therapeutic alternatives. Here, the saprophytic fungus Fusarium solani was used to biosynthesize silver nanoparticles (AgNPs), which were characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The AgNPs showed a surface plasmon resonance peak at ~ 410 nm, a zeta potential of - 42.7 mV, an average TEM diameter of 19.58 nm, and a hydrodynamic (DLS) diameter of 121.4 nm with a polydispersity index of 0.302. Against clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates, the AgNPs exhibited minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.1875-0.375 mM, with confocal laser scanning microscopy (CLSM) showing a reduction in bacterial viability from 92.3% to 28.0% and TEM revealing marked ultrastructural membrane damage following treatment. In a murine MRSA wound infection model, AgNPs treatment increased wound healing from 12.33% to 95.33% and reduced bacterial load from 9.90 to 1.10 log CFU/g tissue relative to the untreated infected control, alongside significant downregulation of TNF-α, IL-6, and COX-2 expression and improved histopathological indices of tissue repair (all p < 0.05). These findings indicate that fungal-derived AgNPs possess potent antibacterial and wound-healing properties against MRSA, supporting their potential as a sustainable therapeutic candidate, although further mechanistic and translational studies are needed.