MECHANISMS OF RESISTANCE

Streptococci, including Streptococcus pneumoniae, and enterococci are relatively resistant to gentamicin and most other aminoglycosides owing to failure of the drugs to penetrate into the cell. However, the primary mechanism of resistance to aminoglycosides, especially in gram-negative bacteria, involves the plasmidmediated formation of inactivating enzymes. These enzymes are group transferases that catalyze the acetylation of amine functions and the transfer of phosphoryl or adenylyl groups to the oxygen atoms of hydroxyl groups on the aminoglycoside. decreased uptake also affects