en Infection Control Infection Control پژوهشی اصيل Original Research <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:10.0pt"><span cambria="" style="font-family:"><span style="color:#44546a">Aims:</span></span></span></b> <span style="font-size:10.0pt"><span cambria="" style="font-family:">The ability of Staphylococcus aureus for biofilm formation caused increased bacterial viability in the host environment and antibiotic resistance. The antibacterial effects of plants such as <i>Cydonia oblonga</i> and <i>Hypericum perforatum</i> were known; However synergic effect of them compared to clindamycin was not found in the previous studies. Therefore, the aim of this study was to compare the antibacterial activity of hydroalcoholic extracts of <i>Cydonia oblonga</i>, <i>Hypericum perforatum</i> and synergistic effect of them against clinical isolates of biofilm formation with Clindamycin. </span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:10.0pt"><span cambria="" style="font-family:"><span style="color:#44546a">Materials & Methods:</span></span></span></b><span style="font-size:10.0pt"><span cambria="" style="font-family:"> In this descriptive and analytical study, 148 clinical strains were collected. Phenotypic analysis was performed by concord plate agar method and genotypic checking by PCR genes was performed simultaneously. MIC was obtained by microbroth dilution method. Data were analyzed by SPSS software version 21 and descriptive.</span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:10.0pt"><span cambria="" style="font-family:"><span style="color:#44546a">Findings:</span></span></span></b><span style="font-size:10.0pt"><span cambria="" style="font-family:"> From 148 clinical isolates of Staphylococcus aureus, 95 isolates (64.2%) of Staphylococcus aureus forming biofilm were isolated by Congord Agar phenotypic method which 12 isolates had genes during PCR.icaA.icaD clfA and fnbA. There was a significant difference between groups in MIC, MBC, and ZOI (p=0.0001). However, Clindamycin and <i>Hypericum perforatum </i>hydroalcoholic extract had lower MIC, and MBC against S. aureus biofilm, respectively compared to other interventions. </span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span style="font-size:10.0pt"><span cambria="" style="font-family:"><span style="color:#44546a">Conclusion:</span></span></span></b><span style="font-size:10.0pt"><span cambria="" style="font-family:"> T</span></span><span lang="EN" style="font-size:10.0pt"><span cambria="" style="font-family:">he hydroalcoholic extract of <i>Hypericum perforatum</i> can be prescribed as a complementary medicine in the treatment of S. aureus biofilm, along with clindamycin.</span></span></span></span></span> Staphylococcus Aureus,Biofilm,Cydonia oblonga,Hypericum Perforatum, 233 239 http://jccs.yums.ac.ir/browse.php?a_code=A-10-307-1&slc_lang=en&sid=1 N. Zareifrar 10031947532846005226 10031947532846005226 No Student Research Committee, Yasuj University of Medical Sciences, Yasuj, Iran A. Sharifi 10031947532846005227 10031947532846005227 Yes Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran S.A. Khosravani 10031947532846005228 10031947532846005228 No Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran M. Zoladl 10031947532846005229 10031947532846005229 No Social Determinants of Health Research Center, Yasuj University of Medical Sciences, Yasuj, Iran S.S. Khoramrooz 10031947532846005230 10031947532846005230 No Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran K. Sharifi 10031947532846005231 10031947532846005231 No Student Research Committee, Kazerun Branch, Islamic Azad University, Kazerun, Iran