Let Me Upgrade You: Impact of Mobile Genetic Elements on Enterococcal Adaptation and Evolution

J Bacteriol. 2021 Oct 12;203(21):e0017721. doi: 10.1128/JB.00177-21. Epub 2021 Aug 9.


Enterococci are Gram-positive bacteria that have evolved to thrive as both commensals and pathogens, largely due to their accumulation of mobile genetic elements via horizontal gene transfer (HGT). Common agents of HGT include plasmids, transposable elements, and temperate bacteriophages. These vehicles of HGT have facilitated the evolution of the enterococci, specifically Enterococcus faecalis and Enterococcus faecium, into multidrug-resistant hospital-acquired pathogens. On the other hand, commensal strains of Enterococcus harbor CRISPR-Cas systems that prevent the acquisition of foreign DNA, restricting the accumulation of mobile genetic elements. In this review, we discuss enterococcal mobile genetic elements by highlighting their contributions to bacterial fitness, examine the impact of CRISPR-Cas on their acquisition, and identify key areas of research that can improve our understanding of enterococcal evolution and ecology.

Keywords: CRISPR; antibiotic resistance; enterococci; horizontal gene transfer; mobile genetic elements; phage; pheromone-responsive plasmid; transposon; virulence.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Biological Evolution
  • CRISPR-Cas Systems
  • Enterococcus faecalis / genetics*
  • Enterococcus faecium / genetics*
  • Interspersed Repetitive Sequences / genetics*