title: Characterization of Staphylococcus aureus Biofilm Formation in Urinary Tract Infection.
abstract: 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.
  
  
  CONCLUSIONS
  Our findings reinforce the role of biofilm formation in resistance to antimicrobial agents. Trimethoprimsulfamethoxazole 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.
authors.affiliation: Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Yousefi
authors.affiliation: Dept. of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Pourmand
authors.affiliation: Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Fallah
authors.affiliation: Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Hashemi
authors.affiliation: Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Rahil
authors.initials: R
authors.lastname: Mashhadi
authors.affiliation: Dept. of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Nazari-Alam
keywords: Antibiotic resistance; Biofilm formation; Staphylococcus aureus; Urinary tract infection