title: Detection of aminoglycoside resistance related genes in multidrug-resistant Acinetobacter baumannii isolated from a single institute of Shanghai, China.
abstract: OBJECTIVE
  Aminoglycoside resistance is common in Acinetobacter baumannii. We investigated aminoglycoside resistance genes in clinical multidrug-resistant Acinetobacter baumannii strains isolated from the Chinese population.
  
  
  METHODS
  One-hundred-and-seven strains of multidrug-resistant Acinetobacter baumannii were isolated from Ruijin Hospital in Shanghai, China. The minimum inhibitory concentrations (MICs) of amikacin, kanamycin, tobramycin, gentamicin, netilmicin and neomycin for these strains were determined with agar dilution method. 16S rRNA methylase genes and eight aminoglycoside modifying enzyme genes were tested via polymerase chain reaction.
  
  
  RESULTS
  We found MICs of amikacin, kanamycin, tobramycin, gentamicin, netilmicin and neomycin in these strains with doses of ≥64 μg/mL, ≥64 μg/mL, ≥128 μg/mL, ≥128 μg/mL, ≥32 μg/mL and ≥8 μg/mL, respectively. Most of those strains showed a high-level resistance to aminoglycosides. ArmA was found in 90% (97/107) of the strains. Six modifying enzyme genes, including aac(6')-Ib, aac(6')-II, aac(3)-II, aac(3)-I, aph(3')-I and ant(3")-I were found with a positive rate of 47%, 50%, 28%, 31%, 93% and 96%, respectively.
  
  
  CONCLUSIONS
  Multidrug-resistant Acinetobacter baumannii is highly resistant to aminoglycosides. Resistant genes could coexist in one strain, therefore, strict implementation of infection control measures is essential to avoid the rapid spread or outbreaks of these multidrug-resistant Acinetobacter baumannii in healthcare-associated facilities.
authors.affiliation: Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine Shanghai, Republic of China - chu_haiqing@126.com.
authors.forename: S Z
authors.initials: SZ
authors.lastname: Xiao
authors.forename: L Z
authors.initials: LZ
authors.lastname: Han
authors.forename: H Q
authors.initials: HQ
authors.lastname: Chu
authors.forename: L
authors.initials: L
authors.lastname: Zhao
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: Y X
authors.initials: YX
authors.lastname: Ni
mesh_terms: D040981:Acinetobacter baumannii / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D000617:Aminoglycosides / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001426:Bacterial Proteins / Q000235:genetics*; D002681:China; D004269:DNA, Bacterial / Q000235:genetics* / Q000302:isolation & purification; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D006761:Hospitals; D006801:Humans; D008780:Methyltransferases / Q000235:genetics; D008826:Microbial Sensitivity Tests; D021521:Ribotyping
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008780:Methyltransferases; C035181:rRNA (adenosine-O-2'-)methyltransferase