Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 45 4 2016 04 27 485 493 Masoud YOUSEFI Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran Mohammad Reza POURMAND Dept. of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran AND Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran Fatemeh FALLAH Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran Ali HASHEMI Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran Rahil MASHHADI Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran Ali NAZARI-ALAM Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran 2016 04 27 2016 04 27 Background: The aim of this study was to investigate the antibiotic susceptibility pattern as well as the phenotypic and genotypic biofilm formation ability of Staphylococcus aureus isolates from patients with urinary tract infection (UTI). Methods: A total of 39 isolates of S. aureus were collected from patients with UTI. The antibiotic susceptibility patterns of the isolates were determined by the Kirby-Bauer disk-diffusion. We used the Modified Congo red agar (MCRA) and Microtiter plate methods to assess the ability of biofilm formation. All isolates were examined for determination of biofilm related genes, icaA, fnbA, clfA and bap using PCR method. Results: Linezolid, quinupristin/dalfopristin and chloramphenicol were the most effective agents against S. aureus isolates. Overall, 69.2% of S. aureus isolates were biofilm producers. Resistance to four antibiotics such as nitrofurantoin (71.4% vs. 28.6%, P=0.001), tetracycline (57.7% vs. 42.3%, P=0.028), erythromycin and ciprofloxacin (56% vs. 44%, P=0.017) was higher among biofilm producers than non-biofilm producers. The icaA, fnbA and clfA genes were present in all S. aureus isolates. However, bap gene was not detected in any of the isolates. Conclusion: Our findings reinforce the role of biofilm formation in resistance to antimicrobial agents. Trimethoprim-sulfamethoxazole and doxycycline may be used as an effective treatment for UTI caused by biofilm producers S. aureus. Our results suggest that biofilm formation is not dependent to just icaA, fnbA, clfA and bap genes harbor in S. aureus strains.     https://ijph.tums.ac.ir/index.php/ijph/article/view/6579 https://ijph.tums.ac.ir/index.php/ijph/article/download/6579/5365