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Clinical- and cost-ineffectiveness of targeted methicillin-resistant Staphylococcus aureus screening of high-risk patients admitted to a low-prevalence teaching hospital

      To the Editor:
      The clinical value of institutional methicillin-resistant Staphylococcus aureus (MRSA) screening practices in teaching hospitals remains controversial. MRSA screening has been implemented in both low-prevalence and high-prevalence hospitals. Screening policies vary from universal to targeted screening, according to the local prevalence of this bacterium.
      • Joshi S.G.
      • Hamilton R.J.
      • Emery C.L.
      • Brooks A.D.
      Institutional MRSA screening practice and policies.
      Infection control experts disagree on the optimal approach to MRSA screening. Most hospitals maintain colonized patients on standard precautions and contact precautions are only for MRSA infections.
      • Otter J.A.
      • Herdman M.T.
      • Williams B.
      • Tosas O.
      • Edgeworth J.D.
      • French G.L.
      Low prevalence of methicillin-resistant Staphylococcus aureus carriage at hospital admission: implications for risk-factor-based vs universal screening.
      • Tubbicke A.
      • Hubner C.
      • Wegner C.
      • Kramer A.
      • Fleba S.
      Transmission rates, screening methods and costs of MRSA—a systematic literature review related to the prevalence in Germany.
      • Davis K.A.
      • Stewart J.J.
      • Crouch H.K.
      • Florez C.E.
      Methicillin-resistant Staphylococcus aureus (MRSA) nares colonization at hospital admission and its effect on subsequent MRSA infection.
      Winthrop-University Hospital is a 600-bed, university-affiliated teaching hospital. We have a restricted antibiotic formulary that restricts the use of antibiotics associated with increased MRSA prevalence (eg, ciprofloxacin, ceftazidime, and imipenem).
      • Cunha B.A.
      Clinical manifestations and antimicrobial therapy of methicillin-resistant Staphylococcus aureus (MRSA).
      As a result, MRSA prevalence in our hospital is exceedingly low. Because we are a low-prevalence hospital it was thought that targeted surveillance of MRSA in patients admitted from chronic care facilities/nursing homes or from other hospitals and hospital readmissions might predict subsequent MRSA infections in our hospital. Admitted patients are ordinarily put on standard precautions. Patients not colonized by MRSA and those subsequently found to be colonized by MRSA are placed on standard precautions.
      From 2007-2012 our institution conducted targeted MRSA screening to determine if MRSA colonization rates from high-risk admitted patients (ie, patients admitted from other hospitals and nursing home/chronic care facilities and hospital readmissions) is clinically effective or cost-effective. Targeted MRSA screening in our institution is carried out by nasal swab cultures using standard microbiologic identification techniques; we do not utilize polymerase chain reaction (PCR) for MRSA nasal swabs, the cost of which is much higher for MRSA screening. We believe rapid reporting of MRSA via PCR is unnecessary.
      During the targeted MRSA screening period, 35,022 MRSA nasal swabs were performed. Of these, only 2,478 (7.1%) were positive for MRSA and MRSA infection rates remained constant during this period (see Fig 1). For this reason, in 2013 targeted MRSA screening was discontinued.
      Figure thumbnail gr1
      Fig 1Results of targeted methicillin-resistant Staphylococcus aureus (MRSA) surveillance at a 600-bed teaching hospital (2007-2012).
      Based on our recent experience we conclude that targeted MRSA surveillance is not effective at predicting or detecting subsequent nosocomial MRSA infections in our teaching hospital. It was not clinically effective or cost-effective to perform targeted MRSA screening to detect MRSA nasal carriage in patients admitted to our hospital from other hospitals or from nursing homes/chronic care facilities.

      References

        • Joshi S.G.
        • Hamilton R.J.
        • Emery C.L.
        • Brooks A.D.
        Institutional MRSA screening practice and policies.
        Am J Infect Control. 2012; 40: 901
        • Cunha B.A.
        Clinical manifestations and antimicrobial therapy of methicillin-resistant Staphylococcus aureus (MRSA).
        Clin Micro Inf. 2005; 11: 33-42
        • Otter J.A.
        • Herdman M.T.
        • Williams B.
        • Tosas O.
        • Edgeworth J.D.
        • French G.L.
        Low prevalence of methicillin-resistant Staphylococcus aureus carriage at hospital admission: implications for risk-factor-based vs universal screening.
        J Hosp Infect. 2013; 83: 114-121
        • Tubbicke A.
        • Hubner C.
        • Wegner C.
        • Kramer A.
        • Fleba S.
        Transmission rates, screening methods and costs of MRSA—a systematic literature review related to the prevalence in Germany.
        Eur J Clin Microbiol Infect Dis. 2012; 31: 2497-2511
        • Davis K.A.
        • Stewart J.J.
        • Crouch H.K.
        • Florez C.E.
        Methicillin-resistant Staphylococcus aureus (MRSA) nares colonization at hospital admission and its effect on subsequent MRSA infection.
        Clin Infect Dis. 2004; 39: 776-782