Impact of Screening for Methicillin-Resistant Staphylococcus aureus (MRSA) in Pneumonia on Vancomycin Utilization

Abstract

Background: Methicillin-Resistant Staphylococcus aureus (MRSA) is frequently targeted with empiric treatment for pneumonia in the hospital. Obtaining quality lower respiratory tract cultures to promote appropriate de-escalation can be difficult or impractical. Nasal screening for MRSA has a high negative predictive value for MRSA pneumonia and can be an effective tool for early de-escalation. Methods: A pharmacist-driven process for nasopharyngeal MRSA screening of patients prescribed intravenous vancomycin was implemented in October 2018. Vancomycin utilization was extracted from the electronic medical record (EMR) and summarized as days of therapy per 1,000 patient days (DOT/1,000 PD). Vancomycin utilization data for the 6 months following process implementation (November 2018–April 2019) were compared to the same period from the previous year (November 2017–April 2018). Specific patient outcomes data were manually collected for patients prescribed vancomycin for pneumonia during the first 2 months following process implementation (November–December 2018; postintervention group) and comparable months (November–December 2017; preintervention group). Data were analyzed using the ² test (nominal data) and Mann–Whitney U test (continuous data). Results: Total vancomycin utilization decreased from a monthly average of 114 to 95 DOT/1,000 PD (17% reduction) and from 27 to 14 DOT/1,000 PD for pneumonia (48% reduction). In-patient mortality was unchanged following process implementation at 17.2% versus 17.5% in the pre- and postintervention groups, respectively. Other clinical outcomes were also similar between the pre- and postintervention groups (Table 1). Fewer vancomycin levels were obtained following implementation with 34.4% of patients (0.61 levels per patient) having a level obtained in the preintervention group compared to 21.6% (0.30 levels per patient; P.001) in the postintervention group. Conclusions: Nasopharyngeal MRSA screening of patients prescribed vancomycin for pneumonia is an effective antimicrobial stewardship strategy to reduce unnecessary use of anti-MRSA therapy without negatively impacting clinical outcomes.

Funding: None

Disclosures: None