1287: METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS NARES SCREEN LEADS TO VANCOMYCIN DE-ESCALATION IN TRAUMA

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Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) nares swab is a proven screening tool to de-escalate vancomycin therapy due to its high negative predictive value in pneumonia and other infections. However, data are lacking on the utility of this test in the critically ill trauma population, which is at high risk for hospital-acquired infections. This study evaluated the impact of empiric MRSA PCR nares screening on de-escalation of vancomycin therapy in critically ill trauma patients. Methods: This is a single center, pre-post observational cohort study conducted at an academic, level I trauma center. Adult patients who were admitted for trauma and received empiric vancomycin therapy for suspected infection in the trauma intensive care unit were included. Patients were grouped by whether they were included 6 months before (pre-cohort) and 6 months after (post-cohort) the implementation of empiric rapid MRSA PCR nares screening in September 2021. The primary outcome was duration of vancomycin therapy. Secondary outcomes included rate of acute kidney injury (AKI), positive MRSA screen or cultures, ICU length of stay (LOS), hospital LOS, and mortality. Results: One-hundred fifty-eight patients were included: 82 in the pre-cohort group and 76 in the post-cohort group. Ninety vancomycin initiation orders were observed in the pre-cohort versus 80 orders in the post-cohort. Baseline demographics were similar between groups. There was a significantly higher rate of MRSA PCR orders in the post-cohort group (75%) compared to (21%) in the pre-cohort (p< 0.001). The pre-cohort group had higher rates of positive MRSA screens (26 vs. 13%, p=0.18) and MRSA positive cultures (17 vs. 9%, p=0.22) compared to post-cohort. There were no reported instances of positive MRSA cultures with a negative PCR. Vancomycin duration was significantly shorter in the post-cohort group (2.55 days vs. 3.5, p=0.02). Hospital and ICU LOS, rates of AKI, and mortality were not different between groups. Conclusions: Implementation of empiric rapid MRSA nares screening led to a shorter overall duration of vancomycin therapy by nearly one day in critically ill trauma patients. Further study is required to evaluate the potential cost savings of empiric MRSA screening in critically ill trauma patients.