Multicenter Study Evaluating the Vitek MS System for Identification of Medically Important Yeasts

Westblade, Lars F.; Jennemann, Rebecca; Branda, John A.; Bythrow, Maureen; Ferraro, Mary Jane; Garner, Omai B.; Ginocchio, Christine C.; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Procop, Gary W.; Richter, Sandra; Rychert, Jenna; Sercia, Linda; Burnham, Carey‐Ann D.

doi:10.1128/jcm.00680-13

Cited by 92 publications

(66 citation statements)

References 36 publications

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“…The present study is the first to evaluate the performance of the Vitek MS v2.0 system for the identification of invasive yeast isolates in China and only the second reported study of the Vitek MS v2.0 system for yeast identification. Our results are comparable to findings from the previous single Vitek MS v2.0 system study, where Ͼ96% of the 852 isolates were correctly identified to the species level, 2.8% were not identified, and 0.6% were misidentified (23).…”

Section: Discussionsupporting

confidence: 81%

“…Several studies have evaluated the performance of the Vitek MS system with database version 1.0 in yeast identification (20)(21)(22). However, there is only one reported study that evaluated the performance of the Vitek MS system with database v2.0 (incorporating 755 species, including 645 bacterial and 110 fungal taxa) for yeast identification (23). In addition, there have been no studies that evaluated the application of the Vitek MS v2.0 system in a large fungal surveillance program such as CHIF-NET where a diverse range of yeasts are encountered.…”

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confidence: 99%

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Yeast Identification Algorithm Based on Use of the Vitek MS System Selectively Supplemented with Ribosomal DNA Sequencing: Proposal of a Reference Assay for Invasive Fungal Surveillance Programs in China

Zhang

Xiao

et al. 2014

J Clin Microbiol

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c Sequence analysis of the internal transcribed spacer (ITS) region was employed as the gold standard method for yeast identification in the China Hospital Invasive Fungal Surveillance Net (CHIF-NET). It has subsequently been found that matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is potentially a more practical approach for this purpose. In the present study, the performance of the Vitek MS v2.0 system for the identification of yeast isolates collected from patients with invasive fungal infections in the 2011 CHIF-NET was evaluated. A total of 1,243 isolates representing 31 yeast species were analyzed, and the identification results by the Vitek MS v2.0 system were compared to those obtained by ITS sequence analysis. By the Vitek MS v2.0 system, 96.7% (n ‫؍‬ 1,202) of the isolates were correctly assigned to the species level and 0.2% (n ‫؍‬ 2) of the isolates were identified to the genus level, while 2.4% (n ‫؍‬ 30) and 0.7% (n ‫؍‬ 9) of the isolates were unidentified and misidentified, respectively. After retesting of the unidentified and misidentified strains, 97.3% (n ‫؍‬ 1,209) of the isolates were correctly identified to the species level. Based on these results, a testing algorithm that combines the use of the Vitek MS system with selected supplementary ribosomal DNA (rDNA) sequencing was developed and validated for yeast identification purposes. By employing this algorithm, 99.7% (1,240/1,243) of the study isolates were accurately identified with the exception of two isolates of Candida fermentati and one isolate of Cryptococcus gattii. In conclusion, the proposed identification algorithm could be practically implemented in strategic programs of fungal infection surveillance.T he global antifungal surveillance programs have provided important global epidemiology and susceptibility data for invasive yeast infections (1-6). In July 2009, the multicenter nationwide China Hospital Invasive Fungal Surveillance Net (CHIF-NET) study was established, and since then it has provided important information on the epidemiology of fungal diseases in China (7). The importance of confirmatory identification in fungal surveillance programs has been highlighted by reports that the initial identifications by the participating laboratories may be inaccurate, particularly for isolates that are uncommon or have unusual biochemical or phenotypic profiles (7,8). Currently, sequencing-based methods are recognized as the gold standard for identifying yeast species (9). In the 2010 CHIF-NET surveillance study, all 814 isolates were confirmed by internal transcribed spacer (ITS) region sequencing in a central laboratory (7). However, the subsequent expansion of the CHIF-NET program has led to a dramatic increase in the numbers of both the participating laboratories and the referred isolates, precluding the universal application of the high-cost and labor-intensive sequence-based identification methods.Recently, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass...

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Section: Discussionsupporting

confidence: 81%

mentioning

confidence: 99%

Yeast Identification Algorithm Based on Use of the Vitek MS System Selectively Supplemented with Ribosomal DNA Sequencing: Proposal of a Reference Assay for Invasive Fungal Surveillance Programs in China

Zhang

Xiao

et al. 2014

J Clin Microbiol

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“…The use of matrixassisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the rapid identification of clinical yeast and mycobacterial isolates has been evaluated in some studies (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). However, there has been a limited number of direct comparison studies focusing on the performance of the two MALDI-TOF systems to rapidly identify yeast and mycobacterial clinical isolates (26)(27)(28).…”

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confidence: 99%

Advantages of Using Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry as a Rapid Diagnostic Tool for Identification of Yeasts and Mycobacteria in the Clinical Microbiological Laboratory

et al. 2013

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“…T o date, literature-based evidence has accumulated with respect to the reliability of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of yeast isolates in diagnostic clinical microbiology laboratories (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). As already shown with bacteria, MALDI-TOF MS identifies yeasts with rapidity, accuracy, and superiority over conventional phenotypic methods (for review, see references [11][12][13][14][15].…”

mentioning

confidence: 99%

Development and Validation of an In-House Database for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Yeast Identification Using a Fast Protein Extraction Procedure

et al. 2014

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In recent studies evaluating the usefulness of the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based identification of yeasts for the routine diagnosis of fungal infections, preanalytical sample processing has emerged as a critical step for reliable MALDI-TOF MS outcomes, especially when the Bruker Daltonics Biotyper software was used. In addition, inadequate results often occurred due to discrepancies between the methods used for clinical testing and database construction. Therefore, we created an in-house MALDI-TOF MS library using the spectra from 156 reference and clinical yeast isolates (48 species in 11 genera), which were generated with a fast sample preparation procedure. After a retrospective validation study, our database was evaluated on 4,232 yeasts routinely isolated during a 6-month period and fast prepared for MALDI-TOF MS analysis. Thus, 4,209 (99.5%) of the isolates were successfully identified to the species level (with scores of >2.0), with 1,676 (39.6%) having scores of >2.3. For the remaining 23 (0.5%) isolates, no reliable identification (with scores of <1.7) was obtained. Interestingly, these isolates were almost always from species uniquely represented or not included in the database. As the MALDI-TOF MS results were, except for 23 isolates, validated without additional phenotypic or molecular tests, our proposed strategy can enhance the rapidity and accuracy of MALDI-TOF MS in identifying medically important yeast species. However, while continuous updating of our database will be necessary to enrich it with more strains/species of new and emerging yeasts, the present in-house MALDI-TOF MS library can be made publicly available for future multicenter studies.T o date, literature-based evidence has accumulated with respect to the reliability of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of yeast isolates in diagnostic clinical microbiology laboratories (1-10). As already shown with bacteria, MALDI-TOF MS identifies yeasts with rapidity, accuracy, and superiority over conventional phenotypic methods (for review, see references 11-15).As an alternative to the ethanol/formic acid-based procedure, also referred to as complete tube extraction, recommended for use only with the Bruker MALDI Biotyper system (Bruker Daltonics, Bremen, Germany), the on-plate extraction or fast formic acid method (4, 16, 17), which consists of covering the smeared yeast colony with a formic acid solution, was proposed. Using the Bruker Biotyper 3.0 database and spectral scores of Ն1.7 as cutoffs for species-level identification, Theel et al. found that the formic acid-based direct on-plate method yielded identification percentages that were similar to those obtained with the more complex tube-based extraction method (18). Nonetheless, Van Herendael et al. showed that MALDI-TOF MS analysis using the short extraction method is suitable for the rapid identification of yeast isolates but that its use ...

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Multicenter Study Evaluating the Vitek MS System for Identification of Medically Important Yeasts

Cited by 92 publications

References 36 publications

Yeast Identification Algorithm Based on Use of the Vitek MS System Selectively Supplemented with Ribosomal DNA Sequencing: Proposal of a Reference Assay for Invasive Fungal Surveillance Programs in China

Yeast Identification Algorithm Based on Use of the Vitek MS System Selectively Supplemented with Ribosomal DNA Sequencing: Proposal of a Reference Assay for Invasive Fungal Surveillance Programs in China

Advantages of Using Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry as a Rapid Diagnostic Tool for Identification of Yeasts and Mycobacteria in the Clinical Microbiological Laboratory

Development and Validation of an In-House Database for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Yeast Identification Using a Fast Protein Extraction Procedure

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