en The effect of Silver nanoparticles on biofilm production of vancomycin resistant Staphylococcus aureus تخصصي Special پژوهشي orginal article <strong><em>Background & Aims</em></strong>: &nbsp;The increasing rate of vancomycin resistant <em>Staphylococcus aureus</em> (VRSA) with biofilm formation may become a new threat to humans. In such cases, finding an effective treatment strategy such as using Nanotechnology (Nano- drugs) to deal with these types of infections may be promising. This study aimed to investigate the inhibitory effects of silver nanoparticles (SNPs) on biofilm formation of VRSAs.<br> <strong><em>Materials and Methods</em></strong><strong>:</strong> Clinical<em> S. aureus</em> isolates were identified to the species level by conventional methods, and their identities were later confirmed by PCR. Following the determination of susceptibility patterns of the isolates; all the screened <em>S.aureus</em> isolates have been assessed regarding their susceptibility to vancomycin. Detection of <em>van</em>A gene and determination of minimum inhibitory concentrations (MICs) of VRSAs were carried out using PCR and Etest methods, respectively. The biofilm production was assessed on all VRSA isolates in the presence/absence of SNPs using micro-titer plate method.<br> <strong><em>Results</em></strong>: &nbsp;In total, 11 (6.21%) VRSAs were identified among 177 <em>S. aureus</em> clinical isolates. These isolates were included in the biofilm production assay. All of the VRSAs were multidrug resistance and biofilm producers. The inhibitory effect of SNPs in concentration of 250 &micro;g/ml on biofilm formation of VRSA isolates was significant (<em>Pv</em> = 0.01).<br> <strong><em>Conclusion</em></strong>: &nbsp;Based on our findings, SNPs can prevent biofilm formation of VRSAs and applying of these nanoparticles may prohibit from the persistence and colonization of such resistant isolates. Vancomycin Resistant, Staphylococcus aureus, Biofilm, Inhibitory Effects 72 78 http://ijrabms.umsu.ac.ir/browse.php?a_code=A-10-114-1&slc_lang=en&sid=1 Maryam Ghahremani ghahremanymaryam@yahoo.com 1003194753284600745 1003194753284600745 No Urmia university of medical sciences Ali Haghi Ghahremanloi Olia alihaghi13530615@gmail.com 1003194753284600746 1003194753284600746 No Urmia university of medical sciences Yaeghob Sharifi ya.sharifi@gmail.com 1003194753284600744 1003194753284600744 Yes Urmia university of medical sciences