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Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
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Emergence of ampicillin-resistant Enterococcus faecium in Danish hospitals

Camilla H Lester1, Dorthe Sandvang, Stefan S Olsen

  • 1Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark. cal@ssi.dk

The Journal of Antimicrobial Chemotherapy
|September 4, 2008
PubMed
Abstract

Insights

Ampicillin resistance in Enterococcus faecium is increasing in Denmark, with most resistant isolates belonging to clonal complex 17 (CC17). This highlights a growing challenge in hospital-acquired infections.

Area of Science:

  • Clinical microbiology
  • Infectious diseases
  • Epidemiology

Background:

  • Ampicillin-resistant Enterococcus faecium (E. faecium) is a growing concern in European hospitals.
  • Clonal complex 17 (CC17) is frequently associated with ampicillin resistance and hospital-acquired E. faecium infections globally.
  • Data on the prevalence and characteristics of ampicillin-resistant E. faecium in Denmark was limited.

Purpose of the Study:

  • To determine the prevalence of ampicillin resistance in clinical E. faecium isolates in Denmark.
  • To investigate the clonal affiliation of these resistant isolates, particularly their relationship to CC17.

Main Methods:

  • Analysis of microbiology data from Danish clinical laboratories (2002-2006).
  • Collection and analysis of 275 clinical enterococcal isolates from four departments (2004).
  • Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) on 84 ampicillin-resistant E. faecium isolates.

Main Results:

  • A 68% increase in overall enterococcal infections was observed from 2002-2006, primarily driven by a tripling of E. faecium cases.
  • A significant rise in ampicillin-resistant E. faecium isolates was noted.
  • MLST revealed that 98% of ampicillin-resistant E. faecium isolates belonged to CC17, with PFGE indicating clonal spread within hospitals.

Conclusions:

  • Ampicillin-resistant E. faecium has significantly increased in Danish hospitals between 2002 and 2006.
  • The majority of these resistant isolates are associated with the CC17 clonal complex.

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