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

• DOI: 10.1007/s00284-016-1161-2
• Publication Date: 2016-11-17T06:09:38Z
• Authors: Antonio Curtoni; Raffaella Cipriani; Elisa Simona Marra; Anna Maria Barbui; Rossana Cavallo; Cristina Costa
• Keywords: 0301 basic medicine; Bacteria; Bacteremia; Culture Media; 03 medical and health sciences; Blood; Blood Culture; Tandem Mass Spectrometry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Humans; Biological Assay; Bacteremia; Bacteria; Biological Assay; Blood; Blood Culture; Culture Media; Humans; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tandem Mass Spectrometry; Microbiology; Applied Microbiology and Biotechnology

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.