In vitro susceptibility and molecular analysis of gentamicin-resistant enterococci

Diagn Microbiol Infect Dis. 1998 Nov;32(3):141-6. doi: 10.1016/s0732-8893(98)00056-x.

Abstract

Enterococci with gentamicin MICs of 256 to 1,024 micrograms/mL were evaluated for susceptibility to ampicillin plus gentamicin synergism. Sixteen of eighteen enterococcal isolates were not susceptible to synergistic killing by ampicillin plus gentamicin; 11 possessed aac(6')-aph(2"), and 4 possessed aph(2")-Ic. A gentamicin MIC of 512 or 1,024 micrograms/mL predicted lack of ampicillin/gentamicin synergism, but a gentamicin MIC of 256 micrograms/mL did not. For six enterococcal strains possessing the gentamicin-resistance gene aph(2")-Ic, ampicillin plus dibekacin, ampicillin plus netilmicin, and ampicillin plus amikacin produced synergistic killing in five, three, and two strains, respectively.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amikacin / pharmacology
  • Amikacin / therapeutic use
  • Ampicillin / pharmacology*
  • Ampicillin / therapeutic use
  • Animals
  • DNA Primers / chemistry
  • DNA Probes / chemistry
  • DNA Restriction Enzymes
  • Dibekacin / pharmacology
  • Dibekacin / therapeutic use
  • Drug Resistance, Microbial / genetics
  • Drug Synergism
  • Electrophoresis, Agar Gel
  • Enterococcus faecium / drug effects*
  • Enterococcus faecium / genetics
  • Gentamicins / pharmacology*
  • Gentamicins / therapeutic use
  • Gram-Positive Bacterial Infections / drug therapy
  • Gram-Positive Bacterial Infections / microbiology
  • Humans
  • Microbial Sensitivity Tests
  • Netilmicin / pharmacology
  • Netilmicin / therapeutic use
  • Penicillins / pharmacology*
  • Penicillins / therapeutic use
  • Polymerase Chain Reaction

Substances

  • DNA Primers
  • DNA Probes
  • Gentamicins
  • Penicillins
  • Dibekacin
  • Netilmicin
  • Ampicillin
  • Amikacin
  • DNA Restriction Enzymes