2157. Evaluation of the Utility of the MRSA Nasal PCR Assay in a Community Healthcare System

Abstract

BackgroundThe MRSA nasal PCR assay is a rapid, noninvasive test that has demonstrated a strong negative predictive value (NPV), as high as 99%, for ruling out MRSA pneumonia. These findings are based primarily on literature from large academic centers, which have evaluated both the positive predictive value (PPV) and NPV of MRSA nasal PCR assays. Investigators sought to assess the NPV of the MRSA nasal PCR assay to rule out MRSA pneumonia within a community healthcare system. To the best of our knowledge, this is the largest study from a community hospital and the only study from a community healthcare system for the utilization of a nasal PCR assay to rule out MRSA pneumonia.MethodsThis is a multicenter, retrospective study of adult patients with both an MRSA nasal PCR assay and positive respiratory culture (sputum, bronchoalveolar lavage, or endotracheal aspirate). Data were collected from September 2014 through August 2015 at three community hospitals (bed size ranging from 328 to 706) across two states within a healthcare system. The study was approved by the Baptist Memorial Hospital Institutional Review Board. PPV and NPV 95% confidence intervals (95% CI) were calculated as previously described in the literature.ResultsA total of 808 patients were included in the analysis across the three hospitals. The total incidence of MRSA in positive sputum samples was 14.9% across the three facilities. Our study demonstrated an overall NPV of 95.1% (93.2, 96.6%) and a PPV of 65.9% (95% CI 57.2, 73.9%). The high NPV was retained despite unit type, resulting in 94.9% (95% CI 92.7, 96.6%), 96.3% (95% CI 90.8, 99.0%), and 94.7% (95% CI 74.0, 99.9%) for the intensive care units (ICU), medical-surgical units, and the emergency department, respectively (Table 1).ConclusionWe concluded that the high NPV of a negative MRSA nasal PCR assay to rule out MRSA pneumonia persisted within a community hospital system. With the results of our study, we plan to utilize institution-specific data along with previously published literature to encourage earlier discontinuation of anti-MRSA antibiotics in patients being treated for pneumonia with negative MRSA nasal PCR assays. Our study demonstrates the validity of the assay in the large community hospital setting with similar findings to studies at large academic institutions. Disclosures All authors: No reported disclosures.