title: Phenotypic and genotypic evaluation of fluoroquinolone resistance in clinical isolates of Staphylococcus aureus in Tehran.
abstract: BACKGROUND
  Fluoroquinolones are broad-spectrum antibiotics widely used in the treatment of bacterial infections such as Staphylococcus aureus isolates. Resistance to these antibiotics is increasing.
  
  
  METHODS
  The occurrence of mutations in the grlA and gyrA loci were evaluated in 69 fluoroquinolone-resistant S. aureus isolates from 2 teaching hospitals of Tehran University of Medical Sciences.
  
  
  RESULTS
  Out of the 165 S. aureus isolates, 87 (52.7%) were resistant to methicillin and 69 (41.8%) were resistant to fluoroquinolone. Fluoroquinolone-resistant S. aureus isolates had a mutation at codon 80 in the grlA gene and different mutational combinations in the gyrA gene. These mutational combinations included 45 isolates at codons 84 and 86, 23 isolates at codons 84, 86 and 106 and 1 isolate at codons 84, 86 and 90. Fluoroquinolone-resistant S. aureus isolates were clustered into 33 PFGE types.
  
  
  CONCLUSIONS
  The findings of this study show that the fluoroquinolone-resistant S. aureus strains isolated in the teaching hospitals in Tehran had multiple mutations in the QRDRs region of both grlA and gyrA genes.
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Aligholi
authors.forename: Akbar
authors.initials: A
authors.lastname: Mirsalehian
authors.forename: Shahnaz
authors.initials: S
authors.lastname: Halimi
authors.forename: Hossein
authors.initials: H
authors.lastname: Imaneini
authors.forename: Morovat
authors.initials: M
authors.lastname: Taherikalani
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Jabalameli
authors.forename: Parisa
authors.initials: P
authors.lastname: Asadollahi
authors.forename: Babak
authors.initials: B
authors.lastname: Mohajer
authors.forename: Alireza
authors.initials: A
authors.lastname: Abdollahi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Emaneini
mesh_terms: D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D024841:Fluoroquinolones / Q000494:pharmacology*; D005798:Genes, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D007492:Iran; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*
chemical_list: D024841:Fluoroquinolones