Sequence of the 50-kb conjugative multiresistance plasmid pRE25 from Enterococcus faecalis RE25

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Multiresistance plasmids contribute to the spread of antimicrobial resistance.
• Enterococcus faecalis is a significant opportunistic pathogen.
• Understanding plasmid biology is crucial for combating antibiotic resistance.

Purpose of the Study:

• To determine the complete DNA sequence of the pRE25 plasmid.
• To identify genes responsible for antimicrobial resistance and plasmid maintenance.
• To investigate the transferability of pRE25 between bacterial species.

Main Methods:

• Whole-genome sequencing of the pRE25 plasmid.
• Bioinformatic analysis to identify open reading frames and functional genes.
• Conjugation experiments to assess plasmid transfer.

Main Results:

• The 50,237-bp DNA sequence of pRE25 was determined, revealing 58 putative open reading frames.
• Five genes conferring resistance to 12 antimicrobials were identified, including chloramphenicol acetyltransferase and 23S RNA methylase.
• A 30.5-kb segment showed high similarity to the pIP501 plasmid, and resistance genes were found on a 7.4-kb fragment.
• pRE25 demonstrated conjugative transfer to Enterococcus faecalis, Listeria innocua, and Lactococcus lactis.

Conclusions:

• The pRE25 plasmid possesses a complex genetic structure with significant antimicrobial resistance genes.
• Its ability to transfer between species highlights its potential role in disseminating antibiotic resistance.
• pRE25 may facilitate the spread of resistant microorganisms into the human population via the food chain.