Abstract
Twenty-six strains of multi-resistant Staphylococcus aureus (MRSA) recovered from November 1985 to February 1986 were screened for their plasmid profiles. Among them, 11 strains were recovered from 8 patients with definite nosocomial infections. The results showed that one MRSA strain carrying 5 plasmids with molecular weight ranging from 1.75 .times. 106 to 5 .times. 106 daltons was epidemic in our hospital while 3 other distinct strains caused cross infections in both the burn ward and the medical wards. The epidemic strain and two other hospital-acquired strains were found in identical form in the community, suggesting that the pattern of nosocomial MRSA can be affected by strains outside hospital. The plasmid profile analysis was employed to differentiate the epidemic isolates from the coisolates and to study the relation between clinical isolates. The method is apparently superior to antibiogram.