en Infectious disease (Molecular and Cellular aspects) Infectious disease (Molecular and Cellular aspects) Original Article Original Article <p style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Tahoma;"><span style="line-height:14.0pt">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 <i>Staphylococcus aureus</i> SAU27as a multidrug-resistant strain. The study aimed to evaluate the potential synergistic effects of phage&ndash;nanoparticle combinations in combating biofilm-related infections caused by multidrug-resistant <i>S. aureus</i>. <i>S. aureus</i> 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 &mu;g/mL and 72 &mu;g/mL, respectively. The combination of both nanoparticles reduced the minimum inhibitory concentration to 25 &mu;g/mL. Adding BacPhage-SAU27 further reduced the minimum inhibitory concentration to 15 &mu;g/mL for zinc oxide nanoparticles and 18 &mu;g/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&ndash;nanoparticle combination. The combination of BacPhage-SAU27 with zinc oxide and iron oxide nanoparticles offers a promising strategy to combat <i>S. aureus</i> biofilms and may provide an alternative to antibiotic therapies.</span></span></span></p> Staphylococcusaureus, Antibiotic-resistantbacteria, Phage,Ironandzinc nanoparticles 1196 1215 http://ijmcmed.org/browse.php?a_code=A-10-8440-1&slc_lang=en&sid=1 Ashkan Dirbaziyan Ghadi02107@gmail.com 100319475328460037123 100319475328460037123 No Department of Microbiology, Qo.C., Islamic Azad University, Qom, Iran. Mohammadreza Zolfaghari mo.zolfaghari123@iau.ir 100319475328460037124 100319475328460037124 Yes Department of Microbiology, Ti.t., AJA University of Medical Sciences, Tehran, Iran. Mohammad soleimani m.soleimani@ajaums.ac.ir 100319475328460037125 100319475328460037125 No Department of Microbiology, Ti.t., AJA University of Medical Sciences, Tehran, Iran. Ruhollah Mirjani mirjani@alumnus.tums.ac.ir 100319475328460037126 100319475328460037126 No Department of Genetics and Advanced Technologies, Ti.t., AJA University of Medical Sciences, Tehran, Iran Seyed Soheil Aghaei seyedsoheil.aghaei@iau.ir 100319475328460037127 100319475328460037127 No Department of Microbiology, Qo.C., Islamic Azad University, Qom, Iran.