652. Impact of FilmArray Meningitis Encephalitis Panel on HSV Testing and Acyclovir Use in Children Beyond the Neonatal Period

Background Testing and empiric use of acyclovir for herpes simplex virus (HSV) in children beyond the neonatal period undergoing lumbar puncture for suspected central nervous system (CNS) infection doubled in the past decade, while the incidence of HSV CNS infection is unchanged. A new syndromic multiplex PCR panel (FilmArray Meningitis Encephalitis Panel [MEP]) rapidly detects 14 pathogens in cerebrospinal fluid (CSF), including HSV. The impact of MEP implementation on HSV testing and acyclovir use is unknown. Methods We retrospectively compared CSF testing and acyclovir use in the pre-MEP era January 1, 2007–January 22, 2017 to post-implementation era of MEP January 23, 2017–December 31, 2017 amongst children >60 days with a CSF specimen sent to the Children’s Hospital Colorado microbiology laboratory. HSV singleplex PCR testing was available in both the pre-MEP and MEP eras. Results The proportion of CSF specimens from children with suspected CNS infection undergoing HSV testing (MEP or HSV PCR) doubled from 25% in the pre-MEP era to 54% in the MEP era (P < 0.01; Figure 1). In the MEP era, HSV testing was conducted by MEP in 96% of cases and HSV PCR in 8% of cases. In both eras, a majority of CSF specimens undergoing HSV testing had no pleocytosis (63% vs. 59%, P = 0.27). Children with negative HSV testing by MEP were less likely to be started on acyclovir than those with negative HSV testing by singleplex PCR (18% vs. 50%, P < 0.01) and, amongst those started, acyclovir was discontinued sooner, after a median 3 vs 5 doses (P = 0.05). Overall, however, a similar proportion of children with suspected CNS infection received acyclovir in the MEP and pre-MEP eras (13% vs. 12%), despite a low rate of HSV positivity (0.5% vs. 0%). Conclusion Implementation of MEP for syndromic CSF testing in children >60 days with suspected CNS infection doubled HSV testing without affecting the rate of empiric acyclovir initiation. Patients with negative HSV testing on MEP were less likely to be started on acyclovir, and if started, received fewer doses than those who tested negative on HSV singleplex PCR, likely due to more rapid turnaround time. However, increased MEP testing offset this, suggesting increased use of newer rapid syndromic tests will not cure creeping empiricism. Diagnostic stewardship targeting MEP use toward children with pleocytosis to decrease unnecessary test utilization are warranted. Disclosures All authors: No reported disclosures.