THE USE OF MALDITOF-MS METHOD AFTER LYSIS FILTRATION IN QUICK IDENTIFICATION OF YEASTS
Project no. 103 · Status: Kapanmış · 2017
Summary
OBJECTIVE: Fungal infections are gradually increasing especially in immunodeficiencies and other underlying diseases. Every year, hundreds of thousands of people are seriously affected by invasive candidiasis due to high mortality and morbidity. For this reason, early diagnosis is very important in fungal infections and there is a need for in a short span of time and reliable methods in order to decrease the mortality rate. In this study, the appropriateness of MALDI TOF MS (LC-MS) method after lysis filtration was investigated in order to identify Candida species more quickly. MATERIALS AND METHODS: In this study, 100 Candida strains isolated from positive blood cultures sent to Ege University Faculty of Medicine Microbiology Laboratory between June 2017 and November 2018 were studied by Dalmau plaque, MALDI TOF method and LF-MS method. The MALDI TOF MS identification results after lysis filtration were compared with the results obtained from the classical MALDI TOF MS method and the statistics were analyzed with SPSS v.25,0 Cohen’s Kappa. RESULTS: In our study, 100 Candida species were examined according to conventional and MALDI TOF methods; 37 C. albicans, 23 C. parapsilosis, 17 C. tropicalis, 9 C. glabrata, 6 C. kefyr, 3 C. guilliermondii, 3 C. dubliniensis, 2 C. krusei. LF-MS method in the identification results; 26 C. albicans, 9 C. parapsilosis, 13 C. tropicalis, 9 C. glabrata, 2 C. kefyr, 3 C. dubliniensis, 2 C. krusei. MALDI-TOF method, Dalmau plate and LF-MS method were found to be compatible with 64 origins. It was observed that incompatibility was due to lack of spectrum instead of misidentification. CONCLUSION: The offences which are not defined as "spectrum deficiency ”are in fact the species in the database. Sixty-four Candida species were identified to be 100% compatible with standard methods and this method was found to be advantageous for at least 48 hours according to the MALDI-TOF MS method requiring subculture and at least 72 hours according to Dalmau plaque method. Key words: Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry; Filtration; Candida spp; Candidemia