D. MEINEL¹, C. OTTIGER², O. DUBUIS³, V. HINIC¹, C. STRAUB¹, A. EGLI<sup>1

1</sup>Clinical Microbiology, University Hospital Basel Basel, ²Institute for Laboratory Medicine, Cantonal Hospital Aarau, Aarau, ³Clinical Microbiology, Viollier AG, Allschwil, Switzerland

Background: Immediate and effective treatment in patients with meningitis or encephalitis is associated with improved clinical outcomes. However, the diagnostic prodcedure on cerebrospinal fluid (CSF) is time-consuming, labor-intensive, and due to pre-treatment often unsuccessful. Hence, we aimed to assess the performance of the Filmarray (FA) ME panel (Biofire, Salt Lake City, USA), a new rapid broad panel PCR assay.
Material/methods: The performance of the FA ME panel was compared with routine single PCR assays for viruses, and standard culture procedures for bacteria and yeasts. The FA panel is a nested-PCR and covers 6 bacterial (E. coli K1, H. influenzae, L. monocytogenes, N. meningitidis, S. agalactiae, and S. pneumoniae), 7 viral species (CMV, enterovirus, HSV1, HSV2, HVV6, hum. parechovirus, and VZV), and Cryptococcus neoformans/gattii. A total of 42 CSF samples were examined to determine the overall sensitivity and specificity. Six CSF samples with not-covered bacteria (e.g. S. aureus) were included as specificity controls. The limit of detection was determined by serial dilutions of bacteria and viruses.
Results: 23 samples were tested positive by FA, with21being confirmed by routine diagnostic. Two were culture-negative, however the discrepant FA results were confirmed with an in-house S. pneumoniae PCR and with positive blood-cultures (H. influenza). 19 culture- and PCR-negative samples were also negative with the FA panel. Overall, the sensitivity and specificity was 100%.
In serial dilutions S. pneumoniae, S. agalactiae, L. monocytogenes, N. meningitidis, E. coli K1, and C. neoformans were detected at 60, 7’500, 200, 10, 2’000, and 10 CFU/mL, respectively. For HSV1, HSV2, and VZV the dilutions showed detection limits of 42, 53, and 120 copies/mL, respectively.
Conclusions: The FA ME panel provides a sensitive and rapid PCR-based method for the detection of most common bacterial and viral pathogens associated with meningitis and encephalitis.