Abstract
Two strains isolated from a recent outbreak of infections by gentamicin-resistant Staphylococcus aureus were examined to determine whether genetic control of this resistance is plasmid or chromosomally mediated. Curing techniques indicated a plasmid location in both strains. Physical isolation and characterization of the plasmid deoxyribonucleic acid from one strain revealed that the determinant for gentamicin resistance resides on a 50S plasmid.