A multicenter clinical study to demonstrate the diagnostic accuracy of the genmark dx eplex blood culture identification gram-negative panel

Donna M. Wolk, Stephen Young, Natalie N. Whitfield, Jennifer L. Reid, Adam Thornberg, Karen C. Carroll, Blake W. Buchan, Thomas E. Davis, Hossein Salimnia

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Bacteremia can progress to septic shock and death without appropriate medical intervention. Increasing evidence supports the role of molecular diagnostic panels in reducing the clinical impact of these infections through rapid identification of the infecting organism and associated antimicrobial resistance genes. We report the results of a multicenter clinical study assessing the performance of the GenMark Dx ePlex investigational-use-only blood culture identification Gram-negative panel (BCIDGN), a rapid diagnostic assay for detection of bloodstream pathogens in positive blood culture (PBC) bottles. Prospective, retrospective, and contrived samples were tested. Results from the BCID-GN were compared to standard-of-care bacterial identification methods. Antimicrobial resistance genes (ARGs) were identified using PCR and sequence analysis. The final BCID-GN analysis included 2,444 PBC samples, of which 926 were clinical samples with negative Gram stain results. Of these, 109 samples had false-negative and/or -positive results, resulting in an overall sample accuracy of 88.2% (817/926). After discordant resolution, overall sample accuracy increased to 92.9% (860/926). Pre- and postdiscordant resolution sample accuracy excludes 37 Gram-negative organisms representing 20 uncommon genera, 10 Gram-positive organisms, and 1 Candida species present in 5% of samples that are not targeted by the BCID-GN. The overall weighted positive percent agreement (PPA), which averages the individual PPAs from the 27 targets (Gram-negative and ARG), was 94.9%. The limit of detection ranged from 104 to 107 CFU/ml, except for one strain of Fusobacterium necrophorum at 108 CFU/ml.

Original languageEnglish (US)
Article numbere02484-20
JournalJournal of clinical microbiology
Volume59
Issue number9
DOIs
StatePublished - Sep 2021

Keywords

  • AST
  • Antimicrobial testing
  • Bacteremia
  • GenMark
  • Gram-negative
  • Rapid diagnostics
  • ePlex

ASJC Scopus subject areas

  • Microbiology (medical)

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