Resistance plasmids for inducible macrolide-lincosamide resistance in Staphylococcus simulans and Staphylococcus epidermidis.

Localization and genetic nature of inducible macrolide resistance determinants in some coagulase negative staphylococci (CNS) were studied and compared with those in Staphylococcus aureus. An 1.7-megadalton R-plasmid, pEI 1107, mediating inducible resistance to macrolides and lincosamides was present in part of Staphylococcus simulans and Staphylococcus epidermidis strains isolated in the Central Hospital for Infectious Diseases. Two other plasmids were harboured by S. simulans LK 6108 strain. One of these plasmids, pEI 6108 (molecular mass 5.2 Md) was encoded for inducible macrolide-lincosamide resistance, and the second one, pE 6108 (molecular mass 4.9 Md) for constitutive marcolide resistance. The similarity in size and phenotype of small plasmids in CNS and S. aureus suggest a common origin of these resistance determinants.