1404. The FilmArray Meningitis/Encephalitis (FA ME) May Be of Higher Yield in the Immunocompromised Patient Population

Abstract

BackgroundThe FilmArray® Meningitis/Encephalitis (FA ME) panel is a PCR-based assay that rapidly detects 14 pathogens directly from CSF specimens. After the introduction of this assay at our institution, there was a steady increase in requests for use; however, the positivity rate remained stable. We sought to understand the characteristics of the patients most likely to have a positive FA ME panel, with particular interest in the immune status of each patient.MethodsA retrospective chart review was conducted on 124 patients with suspected infectious meningitis/encephalitis at a large academic tertiary referral center who received FA ME testing between October 2016 and November 2018. Patients were considered immunocompromised if they had received chemotherapy, were solid-organ transplant recipients, or were diagnosed with HIV, autoimmune diseases on immunosuppressants, uncontrolled diabetes, cirrhosis, or hematologic malignancy. Clinical CNS infection was determined using chart review based on culture, serologic, or molecular data.Results60 (48%) patients were immunocompromised and 64 (52%) patients were immunocompetent. Clinical CNS infection occurred in ~25% of immunocompetent (17, 26%) and immunocompromised (17, 28%) patients. However, only 6 immunocompetent patients were found to have a positive FA ME; this accounts for only 35% of the total number of positive FA ME assays during this study period (P = 0.08). Notably, 4 out of 6 patients with cryptococcal meningitis had false-negative results on the FA ME.ConclusionIn spite of the relatively small sample size, there was a trend toward significance in the accurate yield of the FA ME panel in the immunocompromised population compared with the immunocompetent. Our immunocompromised patients appear to be more likely to have an infection which is tested for on the panel. The rates of confirmed CNS infections in both populations were very similar, indicating that immunocompromised patients may benefit more from use of this assay. In our study, immunocompetent patients were more likely to have West Nile infection, for example, which is not on the panel. Additionally, had cryptococcal meningitis been accurately diagnosed by the FA ME, an even greater number of immunocompromised patients would have had a positive FA ME. Disclosures All authors: No reported disclosures.