Influence of a “No MRSA, No Pseudomonas ” Comment to a Respiratory Culture in Antibiotic Utilization During the Treatment of Lower Respiratory Tract Infection

Background: Community-‐acquired pneumonia (CAP) and health care associated pneumonia (HCAP) have an extensive impact health care expenditure and outcomes. Strategies to minimize unnecessary and excessive broad spectrum anRbioRcs (Abx) use are essenRal. In our experience, misclassificaRon of CAP, and over-‐treatment of CAP and HCAP, is common. These errors lead to increased uRlizaRon of Abx with methicillin-‐resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa coverage when they may not be required. As paRents improve on therapy, clinical inerRa makes Abx de-‐escalaRon challenging. Our microbiology lab added the comment “ no MRSA and no Pseudomonas” on negaRve sputum cultures or those with normal respiratory flora growth (Figure 1). Methods: The comment was added to respiratory cultures beginning January 2011. An observaRonal, retrospecRve, analysis was performed on paRents sRll hospitalized 72 hours later, with a negaRve expectorated, induced or tracheal aspirate respiratory culture from 1/2010 through 1/2012. Abx uRlizaRon was evaluated on day -‐1 and day 3. Results: 129 paRents were treated for pneumonia with a negaRve respiratory culture or normal respiratory flora result during the 24 month Rmeframe. 68 paRents 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), anR-‐MRSA and anR-‐Pseudomonal agent use decreased from 0.71 to 0.49 Abx (p=0.008) and 1.24 to 0.96 Abx (p=0.02) respecRvely. The use of parenteral medicaRons decreased from 1.51 to 1.16 Abx (p=0.009). Conclusion: The addiRon of a clear and purposeful “no MRSA, no Pseudomonas” comment improves Abx uRlizaRon. The comment highlights the absence of anRcipated nosocomial pathogens on negaRve or normal respiratory flora cultures analogously to the presence of pathogens in a posiRve culture. Since this comment provides no addiRonal microbiologic informaRon, it emphasizes that clinicians may need reassurance prior to de-‐escalaRon and raises quesRons about the psychology of prescribing. The “No MRSA, no Pseudomonas” comment is one piece to a respiratory culture based anRbioRc stewardship program.