Evaluation of MALDI-TOF mass spectrometry for the identification of medically-important yeasts in the clinical laboratories of Dijon and Lille hospitals

• DOI: 10.3109/13693786.2012.693631
• Publication Date: 2012-12-11T09:27:43Z
• Authors: Boualem Sendid; Patrick Ducoroy; Nadine François; Geraldine Lucchi; Sebastien Spinali; Odile Vagner; Sebastien Damiens; Alain Bonnin; Daniel Poulain; Frederic Dalle
• Keywords: [SDE] Environmental Sciences; 0301 basic medicine; 570; API (R) ID 32C; Time Factors; [SDV]Life Sciences [q-bio]; 610; yeast identification; 03 medical and health sciences; Species Specificity; Yeasts; DNA, Ribosomal Spacer; [SDV.BV]Life Sciences [q-bio]/Vegetal Biology; Humans; [SDV.BV] Life Sciences [q-bio]/Vegetal Biology; Prospective Studies; Mycological Typing Techniques; MALDI-TOF mass spectrometry; uncommon yeast; Reproducibility of Results; Laboratories, Hospital; 3. Good health; [SDV] Life Sciences [q-bio]; Molecular Typing; Mycoses; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; [SDE]Environmental Sciences; Costs and Cost Analysis; France

Conventional identification (CI) of yeasts is based on morphological, biochemical and/or immunological methods. Matrix-assisted laser desorption/ionization - time of flight (MALDI-TOF or MT-MS) mass spectrometry has been proposed as a new method for the identification of microorganisms. This prospective study compared the performance of MT-MS and CI for the identification of yeasts isolated from clinical samples. Sequencing of the internal transcribed spacer (ITS) regions of ribosomal DNA was used as the reference method in the analysis of a total of 1207 yeast isolates. Concordance between MT-MS and CI was observed for 1105 isolates (91.5%), while 74 isolates (6.1%) were misidentified. Molecular identification revealed that 73 of these 74 isolates were identified correctly by MT-MS and CI correctly identified the last one. Concordance between the two techniques was excellent for the medically-important species (98-100%), including the identification of closely-related species (Candida albicans/C. dubliniensis; C. inconspicua/C. norvegensis; C. parapsilosis/C. metapsilosis/C. orthopsilosis). Only 2.3% of isolates belonging to C. famata, C. lambica and C. magnoliae or to Geotrichum spp. and Trichosporon spp. were not identified by MT-MS. This investigation highlights the potential of MT-MS-based yeast identification as a reliable, time and cost-efficient alternative to CI.