title: Presence of exoY, exoS, exoU and exoT genes, antibiotic resistance and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran.
abstract: BACKGROUND
  Pseudomonas aeruginosa, as Gram-negative rod bacilli, has an important role in human infection. In the present study we aimed to investigate the presence of exo genes and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran.
  
  
  METHODS
  160 isolates of P. aeruginosa were collected and identified by biochemical tests and were characterized for antibiotic resistance. Biofilm production was evaluated by microtiter plate assay and the presence of exo genes was evaluated by allele-specific PCR (polymerase chain reaction). Chi-square test was used for statistical analysis.
  
  
  RESULTS
  The most effective antibiotics against isolates were colistin and polymyxin B. 87% of the isolates were biofilm producers of which 69% were strongly biofilm producers. 55% of the isolates carried exoY, 52% of the isolates carried exoU, and 26.3% and 5% carried exoS and exoT, respectively.
  
  
  CONCLUSIONS
  Our findings showed different distribution of exo genes in clinical isolates of P. aeruginosa in Northwest Iran. ExoS and exoU were more prevalent in non-biofilm producers and exoY was more prevalent in biofilm producer isolates. These results might indicate the importance of exoY in biofilm production of Pseudomonas aeruginosa.
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Azimi
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Hossein Samadi
authors.initials: HS
authors.lastname: Kafil
authors.affiliation: Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Hossein Bannazadeh
authors.initials: HB
authors.lastname: Baghi
authors.affiliation: Infectious Disease and Tropical Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Shokrian
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Khadijeh
authors.initials: K
authors.lastname: Najaf
authors.affiliation: Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Asgharzadeh
authors.affiliation: Infectious Disease and Tropical Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Yousefi
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Firooz
authors.initials: F
authors.lastname: Shahrivar
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Medical Microbiology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Aghazadeh
keywords: Pseudomonas aeruginosa; biofilm; exo genes; infection; type III secretion system