Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Method for Discrimination between Molecular Types of Cryptococcus neoformans and Cryptococcus gattii

Posteraro, Brunella; Vella, Antonietta; Cogliati, Massimo; Carolis, Elena De; Florio, Ada Rita; Posteraro, Brunella; Sanguinetti, Maurizio; Tortorano, Anna Maria

doi:10.1128/jcm.00737-12

Cited by 90 publications

(77 citation statements)

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“…As an example, its database was not able to distinguish the recently identified C. metapsilosis and C. orthopsilosis within the so-called C. parapsilosis complex, species with different propensities for biofilm production (19,20). A similar behavior was also observed in relation to Cryptococcus gattii misidentified by VMS as C. neoformans, two species whose prompt differentiation may allow more accurate treatment choices (21,22). Importantly, all misidentifications, including those regarding rarer species, were reported with a high confidence score, indicating the actual major drawback of VMS.…”

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confidence: 72%

Comparative Evaluation of the Bruker Biotyper and Vitek MS Matrix-Assisted Laser Desorption Ionization–Time Of Flight (MALDI-TOF) Mass Spectrometry Systems for Identification of Yeasts of Medical Importance

et al. 2013

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We report the first comparative evaluation between the Bruker Biotyper MS (BMS) and the Vitek MS (VMS) for the identification of yeasts. The rate of correct identifications at the species level was comparable using the commercial databases (89.8% versus 84.3%; P ‫؍‬ 0.712), but higher for BMS using an in-house-extended database (100% versus 84.3%; P ‫؍‬ 0.245). Importantly, the rate of misidentification was significantly higher for VMS (1% versus 12.1%; P < 0.0001), including the rate of major errors (0% versus 4.5%; P ‫؍‬ 0.0036). The introduction of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in the clinical microbiology laboratories is changing the approach to bacterial and fungal identification (1-4). In particular, several studies have already demonstrated the reliability of MALDI-TOF MS in the rapid identification of yeasts in different clinical settings (5-7), evidencing its cost-effectiveness in allowing the initiation of species-targeted antifungal therapy (7-9). To date, four MALDI-TOF MS systems are commercially available: the Microflex LT Biotyper (Bruker Daltonics, Bremen, Germany) (BMS), the Saramis system (bio-Mérieux, Marcy l'Etoile, France), the Vitek MS system (bioMérieux, Marcy l'Etoile, France) (VMS), and, very recently, the Andromas system (Andromas, Paris, France). Several comparative studies have already been performed using the most common systems (BMS and VMS), but, to the best of our knowledge, they have focused only on the identification of bacteria (10-13). Only very recently was a comparative study on yeasts performed using BMS and Saramis (bio-Mérieux, Marcy l'Etoile, France), the previously distributed version of VMS (14). In the present study, we evaluated the ability of BMS and VMS to identify a broad panel of yeasts of medical interest.One hundred ninety-seven isolates from different human samples, previously identified by conventional biochemical techniques or by sequencing the internal transcribed spacer 1 (ITS1) and ITS2 regions, were blindly identified using the two systems. In order to minimize the risk of misidentification related to the use of incomplete and error-filled public databases (15), the sequences obtained were compared to reference data available in two databases: GenBank, searched by using the nucleotide BLAST tool (blast.ncbi.nlm.nih.gov), and the CBS (Centraalbureau voor Schimmelcultures) yeast database (www.cbs.knaw.nl). The panel included 157 (79.7%) isolates belonging to 30 Candida or Candida-related species (Table 1), and 40 (20.3%) isolates belonging to 15 non-Candida species (Table 2). Before processing for MS identification, each isolate was cultured on Sabouraud dextrose (Kima, Padua, Italy) agar and incubated for 24 h at 35°C. For BMS, proteins were extracted as recommended by the manufacturer. Briefly, a loopful of yeasts was suspended in one volume of water and three volumes of absolute ethanol, and after centrifugation, the pellets were processed with an equal amount of formic acid and acetonitrile ...

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confidence: 72%

Comparative Evaluation of the Bruker Biotyper and Vitek MS Matrix-Assisted Laser Desorption Ionization–Time Of Flight (MALDI-TOF) Mass Spectrometry Systems for Identification of Yeasts of Medical Importance

et al. 2013

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“…These newly delimited taxa differ in their clinical manifestations, in their prevalence among different patient groups, and in some biochemical and physiological aspects (16). Of note for clinical laboratories, MALDI-TOF mass spectrometry can be used to distinguish the seven new species (16,17).…”

Section: Resultsmentioning

confidence: 99%

Name Changes for Fungi of Medical Importance, 2012 to 2015

Warnock

2017

J Clin Microbiol

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“…In this context, the recent appearance of biophysical methods, such as MALDI-TOF MS, in routine diagnostic microbiology laboratories holds the promise of significantly accelerating the detection of infections caused by fungal pathogens that are resistant to one or more antifungals (19,21). We have already witnessed the use of MALDI-TOF MS being expanded from fungal identification to antifungal susceptibility testing (19,(42)(43)(44). Thus, the present study extends our previous observations by demonstrating that the proposed simplified procedure, i.e., ms-AFST, can be used reliably for the accurate detection of CSF-resistant and CSF-susceptible C. albicans.…”

Section: Discussionmentioning

confidence: 99%

Rapid Antifungal Susceptibility Testing by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Analysis

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eThe widespread use of antifungal agents, which is likely to expand with their enhanced availability, has promoted the emergence of drug-resistant strains. Antifungal susceptibility testing (AFST) is now an essential procedure for guiding appropriate antifungal therapy. Recently, we developed a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based method that enables the detection of fungal isolates with reduced echinocandin susceptibility, relying on the proteome changes that are detectable after a 15-h exposure of fungal cells to serial drug concentrations. Here, we describe a simplified version of this approach that facilitates discrimination of the susceptible and resistant isolates of Candida albicans after a 3-h incubation in the presence of "breakpoint" level drug concentrations of the echinocandin caspofungin (CSF). Spectra at concentrations of 0 (null), 0.03 (intermediate), and 32 (maximal) g/ml of CSF were used to create individual composite correlation index (CCI) matrices for 65 C. albicans isolates, including 13 fks1 mutants. Isolates are then classified as susceptible or resistant to CSF if the CCI values of spectra at 0.03 and 32 g/ml are higher or lower, respectively, than the CCI values of spectra at 0.03 and 0 g/ml. In this way, the drug resistance of C. albicans isolates to echinocandin antifungals can be quickly assessed. Furthermore, the isolate categorizations determined using MALDI-TOF MS-based AFST (ms-AFST) were consistent with the wild-type and mutant FKS1 genotypes and the AFST reference methodology. The ms-AFST approach may provide a rapid and reliable means of detecting emerging antifungal resistance and accelerating the initiation of appropriate antifungal treatment.

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Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Method for Discrimination between Molecular Types of Cryptococcus neoformans and Cryptococcus gattii

Cited by 90 publications

References 39 publications

Comparative Evaluation of the Bruker Biotyper and Vitek MS Matrix-Assisted Laser Desorption Ionization–Time Of Flight (MALDI-TOF) Mass Spectrometry Systems for Identification of Yeasts of Medical Importance

Comparative Evaluation of the Bruker Biotyper and Vitek MS Matrix-Assisted Laser Desorption Ionization–Time Of Flight (MALDI-TOF) Mass Spectrometry Systems for Identification of Yeasts of Medical Importance

Name Changes for Fungi of Medical Importance, 2012 to 2015

Rapid Antifungal Susceptibility Testing by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Analysis

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