116 - Leveraging the Use of the PCR-based Methicillin-Resistant Staphylococcus aureus (MRSA) Nasal Swab in the Emergency Department to Optimize Vancomycin Use in the Inpatient Setting

Background: The MRSA nasal swab has been shown to have a negative predictive value of 97-100% for an MRSA infection. Therefore, a negative MRSA swab can be an important antimicrobial stewardship tool to stop unnecessary empiric anti-MRSA therapy. Prolonged anti-MRSA therapy may increase hospital length stay, adverse effects, antimicrobial resistance, and increase the risk of acute kidney injury. Timely obtainment of the MRSA nasal swab is paramount to prevent these complications. To improve the timely collection at our institution, we linked the MRSA nasal swab order with the initial order for vancomycin in the ED using the electronic medical record.

Methods: This was a single-center, retrospective review of adult ED patients (≥ 18 years) who recieved vancomycin at Yale New Haven Hospital, New Haven, CT, USA and had an MRSA nasal swab collected. The pre-intervention cohort were patients who met inclusion criteria between September 2018 and October 2018. The post-intervention cohort, following the linking of the MRSA nasal swab with the vancomycin order included patients between June 2019 and July 2019. The primary endpoint was the time from the ED visit to vancomycin discontinuation in patients with a negative MRSA nasal swab. The secondary endpoint was a comparison of inpatient vancomycin usage before and after implimentation of the intervention.

Results: In the pre-intervention cohort 665 patients were reviewed with 100 meeting inclusion criteria and in the post-intervention cohort 242 patients were reviewed with 100 meeting inclusion criteria. Baseline demographic characteristics were similar between the two cohorts. For the primary endpoint, the time from ED visit until vancomycin discontinuation was 61 hours in the pre-intervention cohort versus 34 hours in the post-intervention cohort (p< 0.001). The secondary endpoint of the impact of the intervention on vancomycin usage is depicted figure attached.Vancomycin IV Days of Therapy/1000 Patient Days Before and After Intervention


Conclusion: Linking the MRSA nasal swab order with the order for vancomycin in the ED led to a significantly shorter time of empiric vancomycin which in turn resulted in an overall reduction in the use of vancomycin.