Author/Authors :
Hedayati, Mohammad Taghi Invasive Fungi Research Center - Mazandaran University of Medical Sciences, Sari, Iran , Ansari, Saham Department of Medical Parasitology and Mycology - School of Medicine - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Ahmadi, Bahram Department of Medical Laboratory Sciences - Faculty of Paramedical - Bushehr University of Medical Sciences, Bushehr, Iran , Taghizadeh Armaki, Mojtaba Department of Medical Parasitology and Mycology - School of Medicine - Babol University of Medical Sciences, Babol, Iran , Shokohi, Tahereh Invasive Fungi Research Center - Mazandaran University of Medical Sciences, Sari, Iran , Abastabar, Mahdi Invasive Fungi Research Center - Mazandaran University of Medical Sciences, Sari, Iran , Er, Halil Department of Microbiology - Faculty of Medicine - University of Akdeniz, Antalya, Turkey , Ozhak, Betil Department of Microbiology - Faculty of Medicine - University of Akdeniz, Antalya, Turkey , Ogunç, Dilara Department of Microbiology - Faculty of Medicine - University of Akdeniz, Antalya, Turkey , Ilkit, Macit Department of Microbiology - Division of Mycology - Faculty of Medicine, University of Cukurova, Adana, Turkey , Seyedmousavi, mojtaba Center of Expertise in Microbiology - Infection Biology and Antimicrobial Pharmacology, Tehran, Iran
Abstract :
Background and Purpose: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used to discriminate among pathogenic microorganisms in clinical laboratories. The aim of this study was to assess the utility of MALDI-TOF MS in the routine identification of clinical dermatophyte isolates obtained from various geographical regions of Iran.
Materials and Methods: A total of 94 isolates, including Trichophyton interdigitale (n=44), T. rubrum (n=40), T. tonsurans (n=4), Microsporum canis (n=4), and Epidermophyton floccosum (n=1), were analyzed in this study. The identity of each isolate was determined by polymerase chani reaction amplification and sequencing of the internal transcribed spacer (ITS) region of nuclear-encoded ribosomal DNA and also MALDI-TOF MS. The obtained data by molecular approach were compared with MALDI-TOF MS.
Results: The MALDI-TOF MS led to the identification of 44 (47%) isolates at the species level by generating the spectral score values of ≥ 2.0. However, there was not sufficient agreement between the results of the molecular-based ITS identification methods and MALDI-TOF MS in the species identification of 16 (17%) isolates. The Bruker Daltonics database was also not able to identify protein spectra related to 12 isolates (13%), including T. interdigitale (n=5), T. rubrum (n=4), M. canis (n=2), and T. tonsurans (n=1).
Conclusion: According to the results, the utility of MALDI-TOF MS as a routine diagnostic tool for the accurate and reliable identification of dermatophytes can be justified whenever the protein spectra of a large set of worldwide clinical isolates are included in the commercial libraries. In addition, MALDI-TOF MS can be alternatively used to construct an in-house reference database.
