High-level resistance to gentamicin in clinical isolates of enterococci

J Infect Dis. 1983 Apr;147(4):751-7. doi: 10.1093/infdis/147.4.751.


Nine clinical isolates of Streptococcus faecalis from a university hospital were found to be resistant to high levels (minimal inhibitory concentration, greater than 2,000 micrograms/ml) of gentamicin, tobramycin, amikacin, streptomycin, and kanamycin. The high-level resistance to these aminoglycosides and resistance to penicillin-aminoglycoside synergism were transferable by conjugation to a susceptible recipient strain. In three strains tested, the aminoglycoside resistance was mediated by four aminoglycoside-modifying enzymes: a 3'-phosphotransferase transferred from two strains, a 2"-phosphotransferase and a 6'-acetyltransferase transferred from all three strains, and a streptomycin adenylyltransferase transferred from two strains. This is the first report of the occurrence of high-level gentamicin resistance in enterococcal isolates from the United States.

MeSH terms

  • Aminoglycosides / pharmacology
  • Anti-Bacterial Agents / pharmacology
  • Conjugation, Genetic
  • Drug Resistance, Microbial
  • Drug Synergism
  • Enterococcus faecalis / drug effects*
  • Enterococcus faecalis / enzymology
  • Enterococcus faecalis / genetics
  • Gentamicins / pharmacology*
  • Hospitals, University
  • Microbial Sensitivity Tests
  • R Factors
  • Transferases / analysis
  • United States


  • Aminoglycosides
  • Anti-Bacterial Agents
  • Gentamicins
  • Transferases