50 - evaluation of Discordant Results Between Filmarray Meningitis/encephalitis Panel and Conventional Testing in Pediatric Patients: A Multi-site Retrospective Cohort Study

Background: FilmArray Meningitis/Encephalitis Panel (ME panel) has a 11% false positive and 2.2% false negative rate compared to conventional testing.  We aim to describe characteristics, treatment decisions and outcomes in pediatric patients with discordant results between ME panel and conventional testing.

Methods: We conducted a multisite (n=4) retrospective review of patients < 18 years with positive cerebrospinal fluid (CSF) results by ME panel or conventional testing (CSF culture, Herpes Simplex Virus [HSV] and enterovirus [EV] PCR) from time of local ME panel implementation to February 2019. We excluded CSF obtained for non-infectious reasons. Demographic and clinical data were extracted from electronic medical records. Comparison between concordant and discordant results were made using Mann-Whitney test for continuous and Fisher’s exact test for categorical variables.

Results: A total of 355 patients had at least 1 positive result. Baseline characteristics and pathogens are shown in Table 1 and 2. Of the 53 bacterial pathogens identifiable by ME panel, 31 (58%) had discordant results – 29 positive by ME panel only and 2 by culture only (both E.coli). Patients with bacterial pathogens identified by ME panel only had lower CSF WBC and protein but higher CSF glucose (Table 3). Five patients with bacteria identified on ME panel only were not treated as meningitis given lack of pleocytosis, no antibiotic pretreatment and negative repeat cultures. Of these, 4 recovered without complications but one had hypoxic encephalopathy.
Two patients had HSV noted in ME panel but individual PCR negative. The first was a 13-day-old with typical skin lesions and positive surface swab. The other was a 6-day old only with CSF pleocytosis. Both had abnormal neuroimaging and were treated as true cases. Of 24 who had both EV PCR and ME panel, 7 were positive by ME panel only and 3 by PCR only.Table 1: Baseline Characteristics of the Study Population
Table 2: Pathogens identified via CSF Culture, ME panel or Conventional PCR
Table 3: Characteristics of Discordant Results for Bacterial Pathogens Tested in ME panel


Conclusion: More than half of bacterial pathogens identified by ME panel did not have a corresponding positive CSF culture. No difference was noted by antibiotic pretreatment. Treatment decisions based on positive ME panel should be made in the appropriate clinical context. Likewise, a negative ME panel does not rule out infection especially when atypical organisms are suspected.

Presenting Author(s)

• 

  Maheswari Ekambaram, MBBS

  Pediatric Hospitalist
  Baylor Scott and White Medical Center
  Round Rock, Texas

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

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Co-Author(s)

• AN

  Aleisha M. Nabower, MD, MHPTT

  Assistant Professor of Pediatrics, Hospital Medicine
  CSP-Children's Specialty Physicians
  Omaha, Nebraska

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• KA

  Krow Ampofo, MBChB

  Dr.
  University of Utah
  Salt Lake City, Utah

  Disclosure: Merck (Grant/Research Support)
• NG

  Nathan S. Gollehon, M.D., MHPTT

  Associate Professor, Division of Neonatology
  University of Nebraska Medical Center
  Omaha, Nebraska

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• NG

  Nathaniel Goodrich, M.D.

  Assistant Professor, Hospital Medicine
  University of Nebraska Medical Center
  Omaha, Nebraska

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• KM

  Kimberly C. Martin, D.O., MPH

  Assistant Professor of Pediatrics, Pediatric Infectious Diseases
  OU- Tulsa School of Community Medicine
  Tulsa, Oklahoma

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• RM

  Russell McCulloh, M.D.

  Associate Professor
  University of Nebraska Medical Center
  Omaha, Nebraska

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• PR

  Prabi Rajbhandari, M.D., FAAP

  Pediatric Hospitalist
  Akron Children's Hospital
  Akron, Ohio

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• JS

  Jessica Snowden, MD, MHPTT

  Professor
  University of Arkansas for Medical Sciences
  Little Rock, Arkansas

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.