Identification of Dermatophytosis Agents by Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry
Ayse Baris11Department of Medical Microbiology, University of Health Sciences, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey Department of Medical Microbiology, Istanbul Medical Faculty, Istanbul University
bjectives: We aimed to evaluate the identification of dermatophytes with Matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS). Methods: 138 dermatophytes were identified by applying ethanol-formic acid-acetonitrile extraction protocol to mold subcultures on solid and broth media, using fungal library of MALDI Biotyper(Bruker Daltonics,Germany) system. Scores of ?1.7 and ?2.0 were used as identification threshold scores. Morphology-based techniques were used as the diagnostic standard methods. Results: With the threshold score of ?2.0; 17.6% of 136 isolates extracted from solid media and 59% of 61 isolates extracted from liquid media could be identified correctly. When the threshold is reduced to 1.7; 61.8% of 136 isolates extreacted from solid media and all of 61 isolates extracted from liquid media could be identified correctly. Regardless of the extraction method, 38.4% and 82.6% of the isolates could be identified at the species level when the threshold score was accepted as ?2.0 and ?1.7, respectively(p<0.001). Conclusion: The MALDI-TOF-MS system is a quite useful complement to conventional methods for dermatophyte diagnosis, particularly when the threshold score was accepted as ?1.7. Primarily extraction from solid media, and if identification cannot be made, subsequent subculture to liquid medium will provide benefits in terms of workload, time, and cost. Keywords: Identification of dermatophyte, MALDI-TOF-MS, MALDI Biotyper, protein extraction
Cite This Article
Baris A. Identification of Dermatophytosis Agents by Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry. EJMI. 2021; 5(3): 354-359
Corresponding Author: Ayse Baris