Stability and expression of the staphylococcal constitutive macrolide-lincosamide-streptogramin B resistance plasmid pE3692 in Staphylococcus aureus and Bacillus subtilis

✍ Scribed by Dr. Jerzy Więckiewicz; Kinga Wójcik

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 380 KB
• Volume: 29
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.3620290207

✦ Synopsis

The constitutive MLS resistance plasmid pE3692 (2.4 kb) from S. uureus and pE3692-9 plasmid derived from pE3692 by in vitro deletion of the small HindIII-HindIII fragment Stat (0.3 kb) were introduced into S. uureus RN450 and B. subtilis UOT0277 strains. The pE3692 plasmid was completly stable in S. uureus RN450, however, in B. subtilis UOT0277 this plasmid was segregationally unstable. Deletion of the Sta t fragment from the pE3692 reduced plasmid stability considerably both in S. aureus and B. subtilis host strains. The lower expression of tylosin-resistance of the erm gene of the pE3692-9 plasmid in B. subtilis UOT0277 strain was also observed.

Macrolides, lincosamides, and streptogramin B (MLS) antibiotics are usually active against gram-positive bacteria. Acquired resistance to MLS antibiotics in these bacteria is due to dimethylation of an adenine residue at position 2058 in the 23s rRNA (WEISBLUM 1985), resulting in markedly reduced affinity between ribosomes and MLS antibiotics. Plasmids which confer resistance to MLS antibiotics encode this rRNA methylase (WEISBLUM 1985).

Although many naturally occurring staphylococcal plasmids are capable of replicating in B. subtilis, the majority of them are segregationally unstable in this new host, particularly in the rec-genetic background (NOVICK et af. 1986 , ALONSO et al. 1987)). The plasmid pE194, conferring constitutive MLS-resistance, originally isolated from S. aureus (IORDANESCU 1976). was reported to be segregationally unstable in B. subtilis. Recently the cop and repF genes which control the replication of the pE 194 plasmid have been mapped (VILLAFANE et al. 1987). It was also postulated that the control of pE194 replication may be similar to control mechanism of the S. aureus plasmid pT181 (VILLAFANE et al. 1987).

In this paper, we compare the plasmid stability and expression in S. aweus RN450 and B. suhtilis UOT0277 strains carrying S. aureus plasmid pE3692 and reconstructed in vitro pE3692-9 plasmid encoding the constitutive resistance to MLS antibiotics.