title: Increasing Prevalence of Aminoglycoside-Resistant Enterococcus faecalis Isolates Due to the aac(6')-aph(2") Gene: A Therapeutic Problem in Kermanshah, Iran.
abstract: BACKGROUND
  Enterococci are important pathogens in nosocomial infections. Various types of antibiotics, such as aminoglycosides, are used for treatment of these infections. Enterococci can acquire resistant traits, which can lead to therapeutic problems with aminoglycosides.
  
  
  OBJECTIVE
  This study was designed to identify the prevalence of, and to compare, the aac(6')-aph(2") and aph(3)-IIIa genes and their antimicrobial resistance patterns among Enterococcus faecalis and E. faecium isolates from patients at Imam Reza hospital in Kermanshah in 2011 - 2012.
  
  
  METHODS
  One hundred thirty-eight clinical specimens collected from different wards of Imam Reza hospital were identified to the species level by biochemical tests. Antimicrobial susceptibility tests against kanamycin, teicoplanin, streptomycin, imipenem, ciprofloxacin, and ampicillin were performed by the disk diffusion method. The minimum inhibitory concentrations of gentamicin, streptomycin, kanamycin, and amikacin were evaluated with the microbroth dilution method. The aminoglycoside resistance genes aac(6')-aph(2") and aph(3")-IIIa were analyzed with multiplex PCR.
  
  
  RESULTS
  The prevalence of isolates was 33 (24.1%) for E. faecium and 63 (46%) for E. faecalis. Eighty-nine percent of the isolates were high-level gentamicin resistant (HLGR), and 32.8% of E. faecium isolates and 67.2% of E. faecalis isolates carried aac(6')-aph(2"). The prevalence of aph(3")-IIIa among the E. faecalis and E. faecium isolates was 22.7% and 77.3%, respectively.
  
  
  CONCLUSIONS
  Remarkably increased incidence of aac(6')-aph(2") among HLGR isolates explains the relationship between this gene and the high level of resistance to aminoglycosides. As the resistant gene among enterococci can be transferred, the use of new-generation antibiotics is necessary.
authors.affiliation: Department of General Practitioner Training, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
authors.forename: Mitra
authors.initials: M
authors.lastname: Khani
authors.affiliation: Department of General Practitioner Training, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
authors.forename: Mahdie
authors.initials: M
authors.lastname: Fatollahzade
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Pajavand
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
authors.forename: Somaye
authors.initials: S
authors.lastname: Bakhtiari
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, IR Iran.
authors.forename: Ramin
authors.initials: R
authors.lastname: Abiri
keywords: Enterococci; High-Level Gentamicin-Resistant; Resistance