Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage upon hospital admission in the Netherlands remains very low (0.08%)

  • Lonneke Bode, Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
  • Heiman Wertheim, Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
  • Jan Kluytmans, Laboratory of Microbiology and Infection Control, Amphia Hospital, Breda, The Netherlands
  • Christina Vandenbroucke-Grauls, Department of Medical Microbiology and Infection Control, VU Medical Center, Amsterdam, The Netherlands
  • Annet Troelstra, Department of Medical Microbiology, University Medical Center, Utrecht, The Netherlands
  • Andreas Voss, Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
  • Henri Verbrugh, Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
  • Margreet Vos, Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands

    • Introduction
    In 1999-2000, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage upon hospital admission in the Netherlands was 0.03% (Wertheim et al). As MRSA rates increase worldwide, we assessed whether MRSA nasal carriage in the Netherlands has increased since 1999-2000 despite the national Search-and-Destroy policy.

    Methods
    Between October 2005 and June 2007, patients admitted to one of five participating Dutch hospitals (Amphia Hospital Breda, Erasmus Medical Center Rotterdam, VU Medical Center Amsterdam, University Medical Center Utrecht, Canisius-Wilhelmina Hospital Nijmegen) were screened for Staphylococcus aureus (S. aureus) nasal carriage upon admission. Colonies from nasal cultures suspected for S. aureus were tested for cefoxitin-susceptibility by disk diffusion. Methicillin resistance was confirmed by a S. aureus specific DNA hybridization test, PBP-2’-Latex agglutination test and mecA PCR.

    Results
    Of 6496 patients who were screened for nasal carriage, seven were MRSA positive (7/6496, 0.11%). At time of screening, one patient was already in isolation because of risk factors as described in the national policy. Another patient was a pig farmer, who would now be categorized as being at high risk for MRSA carriage and isolated according to the updated guidelines. However, he was screened before pig farming was known to be a risk factor. The five remaining patients (5/6496, 0.08%) were not at risk for MRSA. Thus, the prevalence of MRSA carriage in patients without known risk factors as currently defined has increased from 0.03 to 0.08% since 1999-2000. This is not significant (p=0.28, Fisher’s Exact Test).

    Conclusion
    Upon hospital admission, the prevalence of MRSA carriage in the Netherlands remains very low (0.08%). It likely that the Dutch Search-and-Destroy policy, together with a restricted use of antibiotics, is responsible for this low prevalence. To anticipate emerging sources of MRSA it is important that prevalence rates are measured on a regular basis, and that guidelines are immediately updated if needed.