Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 4 1-2 2015 03 03 35 42 EN Reza Khashei Department of Bacteriology & Virology, School of Medicine, Shiraz University of Medical Sciences Shiraz, Iran. Hadi Sedigh Ebrahim-Saraie Department of Bacteriology & Virology, School of Medicine, Shiraz University of Medical Sciences Shiraz, Iran. Mohammad Motamedifar Department of Bacteriology & Virology, School of Medicine, Shiraz University of Medical Sciences Shiraz, Iran AND Shiraz HIV/AIDS Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. Mehrdad Zalipour Department of Bacteriology & Virology, School of Medicine, Shiraz University of Medical Sciences Shiraz, Iran. Jamal Sarvari Department of Bacteriology & Virology, School of Medicine, Shiraz University of Medical Sciences Shiraz, Iran. 2016 08 08 2016 08 08 Introduction: Biofilm producing Staphylococcus aureus is known as one of the major causative agents of infections, failure of implanted devices and persistent infection among hospitalized patients. The aim of the present study was to determine the frequency of biofilm producing S. aureus isolates amongst the clinical specimens. Methods: This cross-sectional study was conducted during 2012 to 2013 in two teaching hospitals in Shiraz, southwest of Iran. Totally, 345 S. aureus isolates from various clinical specimens were included. Biofilm producing isolates were phenotypically detected using Congo Red Agar (CRA) and genotypically by PCR assay for the icaA and icaD genes. Results: Of the 345 S. aureus isolates, 42.3% were methicillin-resistant S. aureus (MRSA) and subsequently 57.7% were methicillin susceptible isolates. The results of CRA plates showed that 77 (52.7%) and 74 (37.2%) of MRSA and MSSA were biofilm producing isolates. The frequency of icaA/D genes among MRSA and MSSA isolates was 127 (87%) and 167 (83.9%), respectively. Conclusion: Such a high rate of icaA/D harboring S. aureus among clinical isolates suggest the risk for establishing persistent infections in the hospital settings. https://jmb.tums.ac.ir/index.php/jmb/article/view/173 https://jmb.tums.ac.ir/index.php/jmb/article/download/173/118