GENETIC-CHARACTERIZATION OF PLASMID PRJ5 OF STAPHYLOCOCCUS-AUREUS COMPARED TO PLASMID PE194

pRJ5, a naturally occurring constitutive macrolide, lincosamide and st reptogramin B (MLS) resistance plasmid of Staphylococcus aureus, was c ompared to pE194, a plasmid that confers the inducible phenotype. pRJ5 was stable in all strains of S. aureus tested, even under growth at 4 3-degrees-C, which distinguished it from pE194 which was shown to be t hermo-sensitive for replication. pRJ5, like pE194, was highly unstable in Bacillus subtilis when the cells were grown in nonselective condit ions. Multimeric forms of pRJ5 DNA were detected in the few cells of B . subtilis that retained this plasmid. pE194 was transduced by phages phi11 and phi443 at frequencies 400 and 20- fold higher, respectively, than pRJ5. Both plasmids were co-transduced with the plasmid pRJ4. pR J5 was shown to be compatible with pE194. Therefore they belong to dis tinct Inc groups. Hybridization studies revealed that pRJ5 shares a 1. 35 kb region of homology to pE194, which is limited to the erm gene, c onferring MLS resistance.