Identification of Uncommon Clinically Important Yeasts and Moulds by the Bruker Biotyper Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) System in a Global Antifungal Surveillance Program

Mariana Castanheira, Leah N. Woosley, Rachel R. Dietrich, Shawn A. Messer, Katie M. Simpson, Ronald N. Jones, Michael A. Pfaller


We report the evaluation of the Bruker Biotyper MS (BMS) system for the identification (ID) of 437 isolates of uncommon species of Candida (106 isolates; 17 species), non-Candida yeasts (100 isolates, 16 species), Aspergillus (164 isolates; 11 species) and non-Aspergillus moulds (57 isolates; 36 species) collected from 68 laboratories in 2012.  Using confidence scores of ≥1.7 to <2.0 for genus only ID and scores of ≥2.0 for species-level ID, BMS correctly IDed 89.8% of yeasts and 85.5% of moulds to the genus level and 71.3% and 73.3%, respectively, to the species-level.  Applying a lower threshold of >1.7 for species-level ID to isolates included in the BMS database improved the accuracy of species ID from 88.7% to 99.0% for Candida, from 65.4% to 91.3% for non-Candida yeasts and from 78.6% to 85.4% for moulds.  BMS gave a result of no identification to those species not included in the database and generated very few (5 total, all moulds) mis-IDs, all of which were correctly IDed at the genus-level.


MALDI-TOF, yeasts, moulds, surveillance

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DOI: http://dx.doi.org/10.18103/mra.v0i3.145


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