Abstract
The genetics of gentamicin resistance in Staphylococcus aureus strains isolated during an outbreak of infection in dermatology department have been studied. The predominant strain of S. aureus did not appear to possess a plasmid mediating gentamicin resistance though one isolate yielded a plasmid coding for penicillin and gentamicin. Three distinct plasmids were isolated from other phage types of S. aureus which appeared towards the end of the epidemic. There appeared to be a stepwise loss of gentamicin resistance in the predominant strain.