en Comparison of Biofilm Formation between Methicillin-Resistant and Methicillin-Susceptible Isolates of Staphylococcus aureus Related Fields Related Fields مقاله کامل Full Length/Original Article <p style="direction: ltr; "><strong>Background:</strong> The aim of this study was to compare the biofilm formation and the prevalence of biofilm-associated genes between the isolates of methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) <em>Staphylococcus aureus</em>.<strong> Methods: </strong>In total, 209 <em>S. aureus</em> isolates were collected. The antibiotic susceptibility test was conducted using nine antibiotics according to the guidelines of Clinical and Laboratory Standards Institute. Phenotypic biofilm formation was performed with microtiter plate assay. The polymerase chain reaction was employed to detect <em>icaA, icaD, icaB, icaC</em>, <em>clfA, clfB</em>, <em>fnbA, fnbB</em>, <em>fib</em>, <em>cna,</em> <em>eno</em>, <em>ebps</em>, <em>bbp,</em> <em>mecA</em>, and SCC<em>mec </em>types as well as <em>agr </em>group genes with specific primers. <strong>Results: </strong>Sixty-four (30.62%) isolates were resistant to methicillin, and 54 (83%) MRSA harbored SCC<em>mec</em> III. Furthermore, 122 (58.3%) isolates belonged to <em>agr</em> group I. Twenty-six (36.1%) MRSA and 42 (28.9%) MSSA isolates were strong biofilm producers (no significant difference). The prevalence of <em>icaA</em>, <em>icaD</em>,<em> icaB</em>, and<em> icaC</em> genes in MSSA isolates was 71, 41, 76, and 72%, respectively. The frequency of <em>clfA, clfB</em>, <em>fnbA, fnbB</em>, <em>fib</em>, <em>cna</em>, <em>eno</em>, <em>ebps</em>, and <em>bbp</em> in MSSA was 100, 100, 56, 46, 74, 54, 78%, 11, and 1%, respectively. However, in MRSA isolates, the frequency was 97, 97, 64, 51, 76, 56, 79, and 12% with no track of <em>bbp</em>, respectively. <strong>Conclusion:</strong> Statistical difference between MSSA and MRSA regarding biofilm formation and the frequency of all biofilm-encoding genes was not significant. The majority of the <em>S. aureus</em> isolates harbored <em>clfA</em>, <em>clfB</em>, <em>eno</em>, <em>fib</em>, <em>icaA</em>, and <em>icaD</em> genes.&nbsp;</p> Biofilm, methicillin-resistant, Staphylococcus aureus 175 181 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-599&slc_lang=en&sid=1 Abdolmajid Ghasemian No Shahin Najar Peerayeh najarp_s@modares.ac.ir Yes Bita Bakhshi No Mohsen Mirzaee No