Rapid Identification of Microorganisms from Positive Blood Culture by MALDI-TOF MS After Short-Term Incubation on Solid Medium

Curr Microbiol. 2017 Jan;74(1):97-102. doi: 10.1007/s00284-016-1161-2. Epub 2016 Nov 17.

Abstract

Matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a useful tool for rapid identification of microorganisms. Unfortunately, its direct application to positive blood culture is still lacking standardized procedures. In this study, we evaluated an easy- and rapid-to-perform protocol for MALDI-TOF MS direct identification of microorganisms from positive blood culture after a short-term incubation on solid medium. This protocol was used to evaluate direct identification of microorganisms from 162 positive monomicrobial blood cultures; at different incubation times (3, 5, 24 h), MALDI-TOF MS assay was performed from the growing microorganism patina. Overall, MALDI-TOF MS concordance with conventional methods at species level was 60.5, 80.2, and 93.8% at 3, 5, and 24 h, respectively. Considering only bacteria, the identification performances at species level were 64.1, 85.0, and 94.1% at 3, 5, and 24 h, respectively. This protocol applied to a commercially available MS typing system may represent, a fast and powerful diagnostic tool for pathogen direct identification and for a promptly and pathogen-driven antimicrobial therapy in selected cases.

Publication types

  • Evaluation Study

MeSH terms

  • Bacteremia / blood
  • Bacteremia / diagnosis
  • Bacteremia / microbiology*
  • Bacteria / chemistry
  • Bacteria / isolation & purification*
  • Bacteria / metabolism
  • Biological Assay
  • Blood / microbiology*
  • Blood Culture
  • Culture Media / metabolism
  • Humans
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Tandem Mass Spectrometry / methods*

Substances

  • Culture Media