AN INCREASE OF 63-KDA PROTEIN PRESENT IN THE CELL-MEMBRANES OF STAPHYLOCOCCUS-AUREUS THAT BEARS A PLASMID MEDIATING INDUCIBLE RESISTANCE TOPARTIAL MACROLIDE AND STREPTOGRAMIN-B ANTIBIOTICS

A plasmid, pEP2104 (23.9 kilobase Pairs), from Staphylococcus aureus c arries a gene that specifies inducible resistance to 14-membered (eryt hromycin, EM, and oleandomycin, OL) and 16-membered macrolide (mycinam icin I and II), but not to all of the latter, and to streptogramin typ e B antibiotics (partial macrolide- and streptogramin-B-antibiotic res istance: PMS-resistance) (L. Janosi, E. Ban, Acta Microbiol. Acad. Sci . Hung., 29, 187 (1982) and Y. Nakajima et al., J. Pharmacobio-Dyn., 1 5, 319 (1992)). The induced cells of strain 8325(pEP2104) did not inac tivate EM, OL, josamycin, rokitamycin or mikamycin B (MKM-B), and the cell-free extract of the strain did not inactivate EM or MKM-B, either . Ribosomes from the cells whose PMS-resistance was induced by EM were sensitive not only to EM or spiramycin, but also to MKM-B. A 63000-da lton protein increased to a great extent only in the cell membrane fra ctions of induced 8325(pEP2104), and may be involved in PMS-resistance .