Aminoglycoside resistance in enterococci

High-level aminoglycoside resistance in enterococci is mediated generally b y aminoglycoside-modifying enzymes, which eliminate the synergistic bacteri cidal effect usually seen when a cell wall-active agent is combined with an aminoglycoside. Clinical microbiology laboratories currently screen for am inoglycoside resistance in enterococci by testing gentamicin and streptomyc in susceptibility. If the recently detected aminoglycoside resistance genes , aph(2")-Ib, aph(2")-Ic, and aph(2")-Id, become more prevalent among clini cal isolates, the approach for detecting susceptibility to aminoglycoside s ynergism in enterococci will require modification. More potent aminoglycosi des need to be developed that will be resistant to modification by a broad spectrum of aminoglycoside-modifying enzymes present in enterococci.