Molecular characterization of the erythromycin resistance plasmid pPV142 from Staphylococcus simulans.

The 2.5-kb erythromycin resistance (EmR) plasmid pPV142 of Staphylococcus simulans 13044 was isolated and characterized. Sequence analysis identified ORF1 and ORF2 encoding a 158-residue replication protein (Rep142) and a 244-residue erythromycin resistance protein (Erm, rRNA adenine N-6-methyltransferase), respectively. Structural analysis and Southern hybridization showed that the rep and ermM genes in pPV142 shared homology with the EmR plasmid pPV141 (2.4 kb) of S. chromogenes 3688 and other EmR plasmids known to exist in staphylococci and bacilli. Based on the presence of a 61-bp repeat upstream of the ermM gene, pPV142 is apparently a unique member of the pSN2 family of EmR plasmid able to express erythromycin resistance constitutively.