560. Meningitis/encephalitis PCR panel result and antimicrobial use in children


 
 
 The meningitis/encephalitis multiplex polymerase chain reaction panel (ME PCR) detects common pathogens associated with community acquired CNS infections. The impact of this test on antimicrobial use in children is not well characterized.
 
 
 
 We performed a retrospective, observational study in children < 18 years of age who had ME PCR performed on CSF collected within 24 hours of admission to the hospital, presentation to the ED, or outpatient encounter from January 2018 to April 2022. Decision to order ME PCR was determined by the treating team. There are no restrictions on ordering ME PCR at our institution. The total calendar days of antimicrobial use from 24 hours prior to CSF collection to 7 days after CSF collection was evaluated. Our primary objective was to compare antimicrobial duration between subgroups based on ME PCR results: negative, virus positive, bacteria positive, and positive for both.
 
 
 
 Of 1282 ME PCR tests performed, 806 were done within the first 24 hours of the encounter. 190 (23.6%) patients never received antimicrobials for empiric treatment of meningitis/encephalitis and were excluded from subsequent analyses. Demographics and antimicrobial use are summarized for patients receiving at least one dose of an antimicrobial in Tables 1 and 2. CSF WBC was highest in bacteria positive CSF (p< 0.001) followed by viral positive (p=0.0066). A positive bacterial result was associated with a longer duration of ceftriaxone, vancomycin and penicillin G and a shorter duration of acyclovir compared to viral and negative results (Table 2). A positive viral result was associated with a shorter length of total antimicrobial treatment (LOT) than negative (p=0.041) and bacterial positive (p< 0.001).
 
 
 
 Positive ME PCR results for bacteria may promote faster initiation of targeted therapy. Positive viral tests were associated with shorter LOT than both negative and bacteria positive ME PCR. Median LOT for negative testing was still 2 days suggesting rapid negative testing does not impact LOT. Prioritizing ME PCR for use in CSF samples with high pretest probability of a positive test may increase its effect on antimicrobial use.
 
 
 
 Anne J. Blaschke, MD, PhD, BioFire Diagnostics/Biomerieux: Advisor/Consultant|BioFire Diagnostics/Biomerieux: Grant/Research Support|BioFire Diagnostics/Biomerieux: IP licensed to BioFire Diagnostics through the University of Utah and royalties received through the University of Utah related to the FilmArray|Merck: Advisor/Consultant.
