1500. Influence of a “no MRSA, no Pseudomonas” Comment to a Respiratory Culture in Antibiotic Utilization During the Treatment of Lower Respiratory Tract Infection
Session: Poster Abstract Session: Antimicrobial Stewardship: Role of Diagnostics
Saturday, October 10, 2015
Room: Poster Hall
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  • Background: Community-acquired pneumonia (CAP) and health care associated pneumonia (HCAP) have an extensive impact on health care expenditure and outcomes. Strategies to minimize unnecessary and excessive broad spectrum Abx use are essential.  In our experience, misclassification of CAP, and over-treatment of CAP and HCAP is common.  These errors lead to increased utilization of Abx with methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa coverage when they may not be required.  As patients improve on therapy, clinical inertia makes Abx de-escalation challenging.  Our microbiology lab added the comment “ no MRSA and  no Pseudomonas”  on negative sputum cultures or those with normal respiratory flora growth (Figure 1). 

    Figure 1.

    Methods: The comment was added to respiratory cultures beginning January 2011. An observational, retrospective, analysis was performed on patients still hospitalized 72 hours later, with a negative expectorated, induced or tracheal aspirate respiratory culture from 1/2010 through 1/2012.  .    Abx utilization was evaluated on day 0 and day 3.  

    Results: 129 patients were treated for pneumonia with a negative respiratory culture during the 24 month timeframe.  68 patients were receiving Abx on day 3. The total number of Abx decreased from 2.31 to 1.87 (p=0.009), broad spectrum use decreased from 1.94 to 1.44 Abx (p=0.004), anti-MRSA and anti-Pseudomonal agent use decreased from 0.71 to 0.49 Abx (p=0.008) and 1.24 to 0.96 Abx (p=0.02) respectively.  The use of parenteral medications decreased from 1.51 to 1.16 Abx (p=0.009).

    Conclusion: The addition of a clear and purposeful “no MRSA, no Pseudomonas” comment improves Abx utilization.   The comment highlights the absence of anticipated pathogens on normal respiratory flora cultures analogously to the presence of pathogens in a positive culture.  Since this comment provides no additional microbiologic information, it emphasizes that clinicians may need reassurance prior to de-escalation and raises questions about the psychology of prescribing.   The “No MRSA, no Pseudomonas” comment is one piece to a respiratory culture based antibiotic stewardship program. 

    Joseph Mcbride, MD1, Lucas Schulz, PharmD2, Barry Fox, MD, FIDSA, FSHEA3, J Dipoto, PharmD2, Nathan Sippel, PharmD4 and Kurt Osterby, BS2, (1)Medicine/Pediatrics - Infectious Disease, University of Wisconsin, Madison, WI, (2)University of Wisconsin Hospital and Clinics, Madison, WI, (3)Department of Medicine, University of Wisconsin, Madison, WI, (4)Pharmacy, Unviersity of Wisconsin, Madison, WI


    J. Mcbride, None

    L. Schulz, None

    B. Fox, None

    J. Dipoto, None

    N. Sippel, None

    K. Osterby, None

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