Purification and characterization of aminoglycoside-modifying enzymes from Staphylococcus aureus and Staphylococcus epidermidis

Several strains of Staphylococcus aureus and Staphylococcus epidermidis, exhibiting characteristic resistance patterns to aminoglycoside antibiotics, were examined. The aminoglycoside-modifying enzymes from these strains were purified by DEAE-Sephadex A-50 chromatography, affinity chromatography, and Sephadex G-100 gel filtration. Three enzymes, a 3'-phosphotransferase III (molecular weight, 31,000; pI 4.1), a bifunctional enzyme having 6'-acetyltransferase and 2"-phosphotransferase (molecular weight, 56,000; pI 4.1) activity, and a 4'4"-adenylytransferase (molecular weight, 34,000; pI 4.7), were isolated from crude extracts of the resistant strains. Aminoglycoside-modifying enzymes with identical enzymatic properties derived from S. aureus and S. epidermidis were also immunologically identical.