Assessment of the Biofire FilmArray Meningitis/Encephalitis Panel’s Role in Antibiotic Stewardship and Clinical Care

Background: The 2006 Healthcare Cost and Utilization Program estimated 72,000 U.S. admissions for meningitis with 45% due to an unspecified virus. Novel molecular techniques, such as the Biofire FilmArray Meningitis/Encephalitis (ME) panel, are increasingly used to improve pathogen detection and time to diagnosis (TtD). The San Antonio Military Medical Center (SAMMC) antibiotic stewardship program (ASP) evaluated the impact of the ME panel on empiric antimicrobial usage.

Methods: The ME panel became available at SAMMC on January 1, 2016 and a retrospective chart review was performed on all hospitalized patients tested by ME panel through April 30, 2016. Demographic data, cerebral spinal fluid (CSF) leukocyte count, immunocompromised status, and intensive care unit (ICU) admission status were collected. TtD by ME panel and CSF culture were compared and days on treatment (DOT) for common antimicrobials were quantified.

Results: Of the 77 ME panels performed during the study period, 54 (70%) were conducted on inpatients and included in the analysis. The majority of patients were males (n=29, 54%) and the median age was 26 years (IQR 45; range 1 day–83 years). A total of 8 (15%) patients were immunocompromised and 17 (31%) required ICU level of care. The median CSF leukocyte was 2 cells/mm³ (IQR 6.5). The median TtD with the ME Panel and CSF culture was 2.75 (IQR 1.48) and 68.5 (IQR 14.5) hours, respectively. The overall median DOT for antimicrobials was 3 (IQR 6.5), whereas the median DOT for individual agents was 2 (IQR 3) for vancomycin (n=15), 1.5 (IQR 1.25) for ceftriaxone (n=16), 3 (IQR 1) for ampicillin (n=15), 3.5 (IQR 1.25) for gentamicin (n=8), 3.5 (IQR 1.75) for cefotaxime (n=6), and 5 (IQR 2.5) for acyclovir (n=7). DOT excluded cases of identified pathogens: human herpes virus 6 (n=2), herpes simplex virus 2 (n=3), enterovirus (n=1), and S. pneumoniae (n=1). No pathogens were recovered by CSF culture.

Conclusion: Despite the recent availability and use of the ME panel in our facility, empiric antibiotics were continued for several days after negative ME panel results. This demonstrates the need for ASP involvement in the use of rapid diagnostic tests by prospectively auditing cases and providing timely feedback in order to reduce unnecessary antimicrobial use.