title: Genetic characterization of Pseudomonas aeruginosa-resistant isolates at the university teaching hospital in Iran.
abstract: BACKGROUND
  Pseudomonas aeruginosa is an opportunistic pathogen that is commonly responsible for nosocomial infections. The aim of this study was to perform a genotyping analysis of the Pseudomonas aeruginosa-resistant isolates by the multilocus sequence typing (MLST) method at the university teaching hospital in Iran.
  
  
  METHODS
  Antimicrobial susceptibility was analyzed for P. aeruginosa isolates. Ceftazidime-resistant (CAZres) isolates with a positive double-disc synergy test were screened for the presence of extended-spectrum β-lactamase-encoding genes. Phenotypic tests to detect the metallo-β-lactamase strains of P. aeruginosa were performed on imipenem-resistant (IMPres) isolates. Selected strains were characterized by MLST.
  
  
  RESULTS
  Of 35 P. aeruginosa isolates, 71%, 45% and 45% of isolates were CAZres, IMPres and multidrug resistant (MDR), respectively. Fifty-seven percent of the isolates carried the bla OXAgroup-1. All the five typed isolates were ST235. Isolates of ST235 that were MDR showed a unique resistance pattern.
  
  
  CONCLUSIONS
  This study shows a high rate of MDR P. aeruginosa isolates at the university teaching hospital in Iran. It seems MDR isolates of P. aeruginosa ST235 with unique resistance pattern disseminated in this hospital.
authors.affiliation: Department of Microbiology, Infectious Diseases and Tropical Medicine Research Center, Isfahan University of Medical sciences, Isfahan, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Fazeli
authors.affiliation: Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran ; Department of Microbiology, Infectious Diseases and Tropical Medicine Research Center, Isfahan University of Medical sciences, Isfahan, Iran.
authors.forename: Hooman
authors.initials: H
authors.lastname: Sadighian
authors.affiliation: Department of Microbiology, Infectious Diseases and Tropical Medicine Research Center, Isfahan University of Medical sciences, Isfahan, Iran.
authors.forename: Bahram Nasr
authors.initials: BN
authors.lastname: Esfahani
authors.affiliation: Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Pourmand
keywords: MDR; MLST; Pseudomonas aeruginosa; ST235