International Journal of Molecular and Cellular Medicine (IJMCM)

This study investigated the combined antibacterial and anti-biofilm effects of zinc oxide nanoparticles, iron oxide nanoparticles, and a newly isolated bacteriophage, BacPhage-SAU27, against Staphylococcus aureus SAU27as a multidrug-resistant strain. The study aimed to evaluate the potential synergistic effects of phage–nanoparticle combinations in combating biofilm-related infections caused by multidrug-resistant S. aureus. S. aureus was cultured and evaluated for biofilm formation. BacPhage-SAU27 was isolated from wastewater using the double-layer agar method and characterized by plaque assays. The minimum inhibitory concentration of zinc oxide nanoparticles and iron oxide nanoparticles was determined individually and in combination, and BacPhage-SAU27 was added to assess interaction effects. Biofilm formation and destruction were analyzed using crystal violet staining and scanning electron microscopy, and the fractional inhibitory concentration index was calculated. The minimum inhibitory concentrations for zinc oxide nanoparticles and iron oxide nanoparticles were 120 μg/mL and 72 μg/mL, respectively. The combination of both nanoparticles reduced the minimum inhibitory concentration to 25 μg/mL. Adding BacPhage-SAU27 further reduced the minimum inhibitory concentration to 15 μg/mL for zinc oxide nanoparticles and 18 μg/mL for iron oxide nanoparticles and lowered the multiplicity of infection to 0.00001. BacPhage-SAU27 alone and in combination with nanoparticles significantly inhibited biofilm formation and caused biofilm destruction. Scanning electron microscopy confirmed damaged biofilm structures and complete bacterial clearance with the phage–nanoparticle combination. The combination of BacPhage-SAU27 with zinc oxide and iron oxide nanoparticles offers a promising strategy to combat S. aureus biofilms and may provide an alternative to antibiotic therapies.