MALDI-TOF MS Versus VITEK®2: Comparison of Systems for the Identification of Microorganisms Responsible for Bacteremia

Abstract

We evaluated the reliability and accuracy of the combined use of MALDI-TOF MS and classical ID VITEK2 to identify monomicrobial infection in blood culture bottles. In total, 70 consecutive positive blood cultures were included in this study. Positive blood culture bottles were subjected to Gram staining and subcultured on solid media. Isolates grown from such culture media were used for classical ID using VITEK2 system. In parallel, an aliquot was subjected to a lysing-centrifugation method and used for the identification with the MALDI-TOF system. Results evidenced the correct genus and species identification of 91.4 % of microorganisms responsible for bacteremia with an agreement to the species and the genus level. If compared with the standard method VITEK2, our simple and cost-effective sample preparation method would be very useful for rapid identification of microorganisms using blood culture bottles. In fact, the direct method showed rapid and reliable results, especially for the gram-negative group.

Método fenotípico automatizado versus método manual na identificação de micro-organismos isolados de hemoculturas: desfechos clínicos e microbiológicos

“…However, an important difference observed is the automated microbiological identification method used by Huang et al 12 , Perez et al 5 and Delport et al 13 : matrix assisted laser desorption ionization-time of flight (MALDI-TOF). This methodology is technically superior to the VITEK® 2 compact 17,18 . MALDI-TOF identifies microorganisms in minutes, while the automated phenotypic method needs hours for identification.…”

Recent Technology of Clinical Microbiology; Whole Genome Sequencing (WGS) and Matrix-Assisted, Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS)

“…VITEK MS (bioMérieux) and Biotyper (Bruker Daltonics) are examples of commercially available MALDI-TOF systems [7,8]. A recent report revealed that the MALDI-TOF assay had high correspondence with a biochemical culture and test (44), and MALDI-TOF and 16S rDNA analysis also had high correspondence, proving that MALDI-TOF is a rapid and accurate method [44,45]. Skin diphtheroids had been regarded as contaminants until MALDI-TOF enabled species identification, and reports of them acting as pathogens has increased [46].…”

Duplex real-time PCR assay for the simultaneous detection ofAchromobacter xylosoxidansandAchromobacterspp

“…are allocated as A. xylosoxidans / A. denitrificans on this platform (18), thus providing limited capacity for accurate species-level identification. Further, VITEK ® MS and other mass spectrometry-based platforms require a purified isolate to obtain an accurate speciation result, which limits the utility of this platform as it cannot be used directly on polymicrobial clinical specimens such as sputum, resulting in longer turn-around times, potentially incorrect antimicrobial treatment, and higher costs (19, 20). In addition, mass spectrometry-based equipment has a large upfront cost and footprint, rendering this method out-of-reach for smaller, less-resourced laboratories.…”