Aminocyclitol-modifying enzymes specified by chromosomal genes in Staphylococcus aureus.

A genetic analysis of aminocyclitol resistance in two strains of Staphylococcus aureus was performed. Resistance of strain FK170, isolated in Zurich, was due to the production of a 3'-phosphotransferase [APH(3')]. Strain 5532, isolated in London, produced a 2"-phosphotransferase [APH(2")] and a 6'-N-acetyltransferase [AAC(6')]. Plasmid deoxyribonucleic acid (DNA) was isolated by isopycnic centrifugation from the two parent strains, as well as from susceptible variants and from resistant transductants of both strains. Comparative analysis of plasmid and from resistant transductants of both strains. Comparative analysis of plasmid DNA by centrifugation in sucrose gradients revealed that strain FK170 harbored a 2.7-megadalton tetracycline R-plasmid and a 36-megadalton cryptic plasmid. Strain 5532 contained an 18.5-megadalton penicillinase plasmid. No evidence for plasmid location of the markers for aminocyclitol resistance could be obtained.