379: PERFORMANCE OF MRSA NARES PCR FOR RULING OUT INFECTIONS IN HOSPITALIZED IMMUNOCOMPROMISED PATIENTS

Introduction: Recent literature demonstrates increasing support for using methicillin-resistant Staphylococcus aureus (MRSA) nasal swab polymerase chain reaction (NaPCR) screening as an effective antimicrobial stewardship tool by aiding early de-escalation of anti-MRSA antimicrobials. However, immunocompromised patients have been underrepresented in these studies despite increased risk of morbidity and mortality from multidrug-resistant organisms (MDRO). The purpose of this study was to determine the negative predictive value (NPV) of the MRSA NaPCR in hospitalized, immunocompromised patients with suspected pneumonia. Methods: This was a single-site, retrospective, observational review of hospitalized, immunocompromised adult patients that had a MRSA NaPCR obtained between March 1, 2020 and January 10, 2021. For inclusion, a confirmed culture result within the two weeks after MRSA NaPCR was required. The primary outcome was the NPV of MRSA NaPCR in hospitalized, immunocompromised patients with suspected pneumonia. Secondary outcomes include NPV in other infections. Results: Between March 1, 2020 and January 10, 2021, 59 patients were included in the study and yielded a total of 76 unique cultures, including 28 respiratory cultures. The NPV of the MRSA NaPCR for pneumonia was 91.7%. The NPV for bloodstream infections was 100% and for urinary tract infections was 100%. Conclusions: The reported NPV of MRSA NaPCR in pneumonia remains high in hospitalized, immunocompromised patients as compared to the NPV reported in literature for immunocompetent patients. The primary limitation of the study was small sample size. MRSA NaPCR has utility as a de-escalation tool in hospitalized, immunocompromised patients.