Reliability of the Verigene system for the identification for Gram-positive Bacteria and detection of antimicrobial resistance markers from children with bacteremia

Abstract

Background: Targeted antimicrobial therapy can reduce morbidity in patients with sepsis. Molecular methodologies used in the clinical laboratory can provide information about infectious agents faster than traditional culture methods. Using molecular information to make clinical decisions more quickly has been shown to improve patient outcomes, and reduce length of stay and healthcare cost in adults. Its effect on pediatric care is less well described.

Methods: Blood cultures growing Gram-positive cocci or Gram-positive bacilli on Gram stain were evaluated by molecular and traditional methodologies. Results from the molecular platform, Luminex Verigene® Blood Culture - Gram-positive Panel (BC-GP) were compared to results from standard culture and susceptibility testing (Vitek™ MS, Vitek™, E-test®). Overall statistical agreement is evaluated.

Results: 1231 positive pediatric blood cultures grew single isolates detectable by the BC-GP panel. 899 were correctly identified to species, 282 to genus, 50 isolates were not detected. All organisms detected by BC-GP that grew in single isolate cultures were identified as the same organism by Vitek™ MS with the exception of 7 organisms.112 cultures were found to have polymicrobial growth of Gram-positive organisms. Excellent overall agreement was noted for antimicrobial resistance markers with only 5 samples displaying discordant results.

Discussion: In general, clinicians can use the identification and antimicrobial resistance marker data gained from Luminex Verigene® BC-GP with confidence to alter empiric coverage. Rare instances of disagreement with traditional culture data led to maintaining the empiric clinical approach and did not result in patient harm.

Keywords: Antimicrobial resistance markers; Blood stream infections; Gram-positive organisms; Molecular identification; Verigene.