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Identification and characterization of a shuttle plasmid with antibiotic resistance gene from Staphylococcus aureus
1Department of Physiology, University of Calcutta, University Colleges of Science & Technology, 92, Acharya Prafulla Chandra Road, Kolkata-700009, India.
Abstract:
While studying antibiotic-resistant plasmids from multi-drug-resistant nosocomial Staphylococcus aureus strains, we isolated a small (2.889 kb) chloramphenicol-resistant (Cm(r)) plasmid, which was designated as pMC524/MBM. The molecular size of pMC524/MBM was close to that of pC194 (2.910 kb), a well-known Cm(r) staphylococcal plasmid. Unlike pC194, this plasmid can replicate and express itself efficiently and stably in Escherichia coli. However, Cm is needed for stable maintenance of pMC524/MBM in different hosts. In this study, the nucleotide sequences of these two plasmids were compared after sequencing of pMC524/MBM [EMBL Accession No. AJ312056 SAU312056]. Although these two plasmids have striking nucleotide sequence homology, the Plus Origin, Minus Origin, the replication protein (Rep), and the chloramphenicol acetyl transferase (Cat) have considerable variations. Possibly, these changes have modulated pMC524/MBM into an efficient shuttle-plasmid.
Insights
A novel chloramphenicol-resistant plasmid, pMC524/MBM, was identified from Staphylococcus aureus. This plasmid exhibits efficient replication in Escherichia coli, functioning as a shuttle vector due to sequence variations compared to pC194.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Antibiotic resistance in nosocomial infections is a growing concern.
- Staphylococcus aureus is a significant pathogen associated with hospital-acquired infections.
- Plasmid-mediated antibiotic resistance contributes to the spread of multi-drug resistance.
Purpose of the Study:
- To characterize a novel chloramphenicol-resistant plasmid, pMC524/MBM, isolated from Staphylococcus aureus.
- To compare the genetic features of pMC524/MBM with the well-characterized staphylococcal plasmid pC194.
- To investigate the potential of pMC524/MBM as a shuttle vector for molecular biology applications.
Main Methods:
- Plasmid DNA isolation and sequencing of pMC524/MBM.
- Comparative sequence analysis of pMC524/MBM and pC194.
- Assessment of plasmid replication and stability in different bacterial hosts (Staphylococcus aureus and Escherichia coli).
Main Results:
- A 2.889 kb chloramphenicol-resistant plasmid, pMC524/MBM, was isolated and sequenced.
- pMC524/MBM shares homology with pC194 but exhibits significant variations in replication origins and genes.
- pMC524/MBM demonstrated efficient and stable replication in both Staphylococcus aureus and Escherichia coli.
- Chloramphenicol was essential for the stable maintenance of pMC524/MBM in various hosts.
Conclusions:
- The sequence variations in pMC524/MBM, particularly in replication elements and the chloramphenicol resistance gene, likely confer its enhanced shuttle vector properties.
- pMC524/MBM represents a valuable tool for molecular cloning and genetic manipulation in both Gram-positive and Gram-negative bacteria.
- Understanding plasmid evolution and function is crucial for combating antibiotic resistance.