Evaluation of matrix‐assisted laser desorption/ionization (MALDI) preparation techniques for surface characterization of intact <i>Fusarium</i> spores by MALDI linear time‐of‐flight mass spectrometry

Kemptner, Jasmin; Marchetti‐Deschmann, Martina; Mach, Robert L.; Druzhinina, Irina S.; Kubicek, Christian P.; Allmaier, Günter

doi:10.1002/rcm.3949

Cited by 76 publications

(67 citation statements)

References 41 publications

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“…Identification of these species is important for patient management, but conventional identification strategies can be difficult due to phenotypic polymorphism. Aspects of MALDI-TOF MS analysis have been investigated for Fusarium, including preanalytical sample preparation (281,282 …”

Section: Fusarium Sppmentioning

confidence: 99%

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

et al. 2013

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SUMMARY Within the past decade, clinical microbiology laboratories experienced revolutionary changes in the way in which microorganisms are identified, moving away from slow, traditional microbial identification algorithms toward rapid molecular methods and mass spectrometry (MS). Historically, MS was clinically utilized as a high-complexity method adapted for protein-centered analysis of samples in chemistry and hematology laboratories. Today, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) MS is adapted for use in microbiology laboratories, where it serves as a paradigm-shifting, rapid, and robust method for accurate microbial identification. Multiple instrument platforms, marketed by well-established manufacturers, are beginning to displace automated phenotypic identification instruments and in some cases genetic sequence-based identification practices. This review summarizes the current position of MALDI-TOF MS in clinical research and in diagnostic clinical microbiology laboratories and serves as a primer to examine the “nuts and bolts” of MALDI-TOF MS, highlighting research associated with sample preparation, spectral analysis, and accuracy. Currently available MALDI-TOF MS hardware and software platforms that support the use of MALDI-TOF with direct and precultured specimens and integration of the technology into the laboratory workflow are also discussed. Finally, this review closes with a prospective view of the future of MALDI-TOF MS in the clinical microbiology laboratory to accelerate diagnosis and microbial identification to improve patient care.

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Section: Fusarium Sppmentioning

confidence: 99%

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

et al. 2013

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“…Species identification by MALDI-TOF MS within the Fusarium genus has not yet been thoroughly investigated. Studies have either focused on the comparison of different sample preparation procedures (45,46) or analyzed only a limited number of Fusarium spp. and strains (47,48).…”

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confidence: 99%

Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Molds of the Fusarium Genus

et al. 2015

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eThe rates of infection with Fusarium molds are increasing, and a diverse number of Fusarium spp. belonging to different species complexes can cause infection. Conventional species identification in the clinical laboratory is time-consuming and prone to errors. We therefore evaluated whether matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a useful alternative. The 289 Fusarium strains from the Belgian Coordinated Collections of Microorganisms (BCCM)/Institute of Hygiene and Epidemiology Mycology (IHEM) culture collection with validated sequence-based identities and comprising 40 species were used in this study. An identification strategy was developed, applying a standardized MALDI-TOF MS assay and an in-house reference spectrum database. In vitro antifungal testing was performed to assess important differences in susceptibility between clinically relevant species/species complexes. We observed that no incorrect species complex identifications were made by MALDI-TOF MS, and 82.8% of the identifications were correct to the species level. This success rate was increased to 91% by lowering the cutoff for identification. Although the identification of the correct species complex member was not always guaranteed, antifungal susceptibility testing showed that discriminating between Fusarium species complexes can be important for treatment but is not necessarily required between members of a species complex. With this perspective, some Fusarium species complexes with closely related members can be considered as a whole, increasing the success rate of correct identifications to 97%. The application of our user-friendly MALDI-TOF MS identification approach resulted in a dramatic improvement in both time and accuracy compared to identification with the conventional method. A proof of principle of our MALDI-TOF MS approach in the clinical setting using recently isolated Fusarium strains demonstrated its validity.

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“…The assessment of MALDI-TOF for species-level identification of filamentous fungi, however, is not as extensive. Many initial fungal MALDI-TOF MS studies focused on isolate identification using purified fungal spores (3,13,15,28). Only more recently has this technology been applied directly to unfractionated fungal colonies (10,11,17).…”

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confidence: 99%

Dermatophyte Identification Using Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

Theel¹,

Hall²,

Mandrekar

et al. 2011

J Clin Microbiol

108

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The performance of the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometer (MS) for the identification of dermatophytes from clinical cultures was compared to that of dermatophyte identification using 28S rRNA gene sequencing. The MALDI Biotyper library (MBL; version 3.0) was used alone and in combination with a supplemented library containing an additional 20 dermatophyte spectra (S-MBL). Acquired spectra were interpreted using both the manufacturer-recommended scores (genus, >1.7; species, >2.0) and adjusted cutoff values established by this study (genus, >1.5; species, >1.7); identifications required a minimum 10% difference in scores between the top two different organisms to be considered correct. One hundred well-characterized, archived dermatophyte isolates and 71 fresh dermatophyte cultures were evaluated using both libraries and both sets of cutoff criteria. Collectively, the S-MBL significantly outperformed the MBL at both the genus (93% versus 37.4%; P < 0,0001) and species (59.6% versus 20.5%; P < 0.0001) levels when using the adjusted score criteria. Importantly, application of the lowered cutoff values significantly improved genus (P ‫؍‬ 0.005)-and species (P < 0.0001)-level identification for the S-MBL, without leading to an increase in misidentifications. MALDI-TOF MS is a cost-effective and rapid alternative to traditional or molecular methods for dermatophyte identification, provided that the reference library is supplemented to sufficiently encompass clinically relevant, intraspecies strain diversity.Dermatophytes, comprising species within the genera Epidermophyton, Microsporum, and Trichophyton, exclusively invade and infect keratinized tissues (i.e., hair, skin, and nails). These organisms are among the most common fungal infections in humans, accounting for over 5 million physician visits annually in the United States (7, 26). Dermatophytes primarily cause superficial dermal mycoses and rarely progress to more invasive disease (8). In the United States, Trichophyton rubrum remains the most common cause of tinea infections and the most frequently isolated dermatophytic pathogen (7,24).Laboratory identification of dermatophytes is typically based on macroscopic observation of colony morphology (i.e., pigmentation, growth rate, texture, etc.) on selective media, followed by microscopic examination of conidia. In addition, specialized Trichophyton agars may be used for differentiation of species within the genera (14). These phenotypic techniques require experienced technologists and are often labor-intensive with a prolonged turnaround time. With the advancement of modern molecular techniques, some laboratories have turned to dermatophyte identification schemes involving sequencing of specific ribosomal DNA regions or real-time PCR amplification of discrete genes (2, 20). While these methods are highly accurate and rapid, they are costly and can be complex to implement.Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) m...

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Evaluation of matrix‐assisted laser desorption/ionization (MALDI) preparation techniques for surface characterization of intact Fusarium spores by MALDI linear time‐of‐flight mass spectrometry

Cited by 76 publications

References 41 publications

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Molds of the Fusarium Genus

Dermatophyte Identification Using Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

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