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Emergence of CC17 Enterococcus faecium: from commensal to hospital-adapted pathogen

Janetta Top1, Rob Willems, Marc Bonten

  • 1Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands. j.top@umcutrecht.nl

FEMS Immunology and Medical Microbiology
|February 19, 2008
PubMed

Insights

Ampicillin-resistant Enterococcus faecium (AREfm) strains, particularly the CC17 lineage, are increasingly causing hospital infections. These VREF strains possess specific genes linked to antibiotic resistance and pathogenicity, posing a growing threat.

Area of Science:

  • Microbiology
  • Epidemiology
  • Genetics

Background:

  • Enterococcus faecium, once a commensal, now causes significant nosocomial infections, especially vancomycin-resistant E. faecium (VREF).
  • The rise of VREF globally followed the emergence of ampicillin-resistant E. faecium (AREfm) in the US.
  • Hospitals with low VRE levels may face similar increases, alongside rising AREfm infections.

Purpose of the Study:

  • To investigate the molecular epidemiology of E. faecium isolates.
  • To identify genetic characteristics associated with hospital-acquired infections.
  • To understand the emergence and spread of resistant strains.

Main Methods:

  • Multilocus sequence typing (MLST) of human and animal E. faecium isolates.
  • Comparative genomic analysis of different E. faecium lineages.
  • Identification of specific genes and genetic elements in hospital-associated strains.

Main Results:

  • MLST revealed host-specific genogroups, including CC17, linked to hospital isolates.
  • CC17 strains exhibit resistance to ampicillin and quinolones.
  • CC17 isolates possess over a hundred hospital-clade-specific genes, including mobile elements, phage genes, and a pathogenicity island with the esp gene.

Conclusions:

  • The CC17 lineage represents a distinct genetic group of E. faecium associated with hospital environments.
  • These hospital-adapted strains carry genetic determinants for antibiotic resistance and potential virulence factors.
  • Understanding these genetic traits is crucial for combating VREF infections in healthcare settings.

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