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Genetic variation and evolution of the pathogenicity island of Enterococcus faecalis

Shonna M McBride1, Phillip S Coburn, Arto S Baghdayan

  • 1Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.

Journal of Bacteriology
|March 10, 2009
PubMed

Insights

The Enterococcus faecalis pathogenicity island (PAI) evolves through modular gene gain via horizontal transfer. Mobile elements likely drive the PAI

Area of Science:

  • Microbiology
  • Genetics
  • Molecular Biology

Background:

  • Enterococcus faecalis is a major cause of hospital-acquired infections.
  • This bacterium readily acquires virulence and antibiotic resistance genes.
  • A 150-kb pathogenicity island (PAI) contributes to E. faecalis pathogenesis.

Purpose of the Study:

  • To investigate the structural variations within the E. faecalis PAI.
  • To understand the genesis and dynamics of PAI evolution.
  • To determine the role of horizontal gene transfer in PAI development.

Main Methods:

  • Multilocus sequence typing (MLST) to analyze strain background relatedness.
  • Microarray analysis to detect variations within the PAI.
  • Comparative analysis of PAI variations across diverse E. faecalis isolates.

Main Results:

  • Evidence of modular gain of gene clusters within the PAI was observed.
  • PAI structural variations occurred independently of chromosomal background.
  • Horizontal transfer is supported as the primary mechanism for PAI gene accretion.

Conclusions:

  • The E. faecalis PAI exhibits modular evolution through the acquisition of gene clusters.
  • Horizontal gene transfer is a key driver for PAI expansion and evolution.
  • Mobile genetic elements likely play a significant role in shaping the E. faecalis PAI.

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