title: High level of gentamicin resistance (HLGR) among enterococcus strains isolated from clinical specimens.
abstract: BACKGROUND
  Enterococci are pathogens that can cause nosocomial infections and acquire resistance properties via several molecular mechanisms. The aac (6')Ie-aph(2″)Ia gene plays a significant role in the emergence of high-level gentamicin-resistant (HLGR) strains. The screening of resistant strains and the provision of appropriate antibiotic therapy can decide the outcome of serious nosocomial infections.
  
  
  METHODS
  In the present study, 142 enterococci were isolated from patients, and the species were identified using standard methods. An antimicrobial susceptibility test was performed using the disc diffusion method, and the minimum inhibition concentration (MIC) of gentamicin was determined according to the broth micro-dilution method. Additionally, PCR was utilized to detect the aac(6')Ie-aph(2″)Ia gene, the presence of which was confirmed by digestion with Sca1 and sequencing.
  
  
  RESULTS
  Of the 142 isolates, 62 (43.7%) were found to exhibit the HLGR phenotype. All except one of the HLGR isolates contained the aac(6')Ie-aph(2″)Ia gene. The prevalence of resistance to other antibiotics and multi-drug resistance (MDR) was higher among the HLGR isolates compared to the non-HLGR isolates.
  
  
  CONCLUSIONS
  Our results indicate that high prevalence rates of MDR and HLGR enterococci are an important problem associated with medical treatment. Furthermore, the presence of the aac(6')Ie-aph(2″)Ia gene was shown to correspond to the presence of the HLGR phenotype among enterococci.
authors.affiliation: Department of Microbiology, Islamic Azad University, Zanjan Branch, Iran.
authors.forename: Narges
authors.initials: N
authors.lastname: Dadfarma
authors.forename: Abbas Ali
authors.initials: AA
authors.lastname: Imani Fooladi
authors.forename: Mahvash
authors.initials: M
authors.lastname: Oskoui
authors.forename: Hamideh
authors.initials: H
authors.lastname: Mahmoodzadeh Hosseini
mesh_terms: D000123:Acetyltransferases / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D018432:Drug Resistance, Multiple; D004586:Electrophoresis; D016983:Enterococcus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005839:Gentamicins / Q000494:pharmacology*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; C108453:6'-aminoglycoside acetyltransferase-2''-aminoglycoside phosphotransferase; D000123:Acetyltransferases; D017853:Phosphotransferases (Alcohol Group Acceptor)