Analysis of the prototypical Staphylococcus aureus multiresistance plasmid pSK1

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• The Staphylococcus aureus multiresistance plasmid pSK1 is a prototype for a family of related plasmids found in epidemic strains.
• These plasmids were initially identified in Australia and later in Europe.

Purpose of the Study:

• To present the complete nucleotide sequence of the pSK1 plasmid.
• To analyze the genetic content and evolution of the conserved region within the pSK1 plasmid family.

Main Methods:

• Complete nucleotide sequencing of the 28.15kb pSK1 plasmid.
• Bioinformatic analysis of the conserved 14kb backbone region.
• Transcriptional profiling to assess host impact.

Main Results:

• The complete 28.15kb nucleotide sequence of pSK1 was determined.
• The conserved 14kb region encodes 12 putative gene products, including a Type I toxin-antitoxin system.
• Plasmid carriage appears to have minimal impact on the host bacterium.

Conclusions:

• The genetic makeup of the pSK1 plasmid family, particularly its conserved backbone, offers insights into plasmid evolution.
• The low host impact associated with pSK1 family plasmids may facilitate the maintenance of multiple resistance determinants.