Comparative Study of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry and Culture Test for iCandida/iIdentification

摘要

Background: A new microorganism identification method using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) has been developed, however, reports on its use for delineating Candida spp. are scarce. Objectives: The purpose of this study was to compare the identification accuracy of mixed infection between culture test and MALDI-TOF MS. Materials and Methods: Eighty-nine denture wearers (average 74.0 ± 9 years) were selected. Specimens were immediately inoculated onto selective medium for CHROMagarTM Candida, and were also carried out using MALDI-TOF MS. The distribution frequencies of them were analyzed. Results: The numbers and rates of detection/non-detection by MALDI-TOF MS of genus Candida were 58/31 (65.2%/34.8%), respectively. Infection types were single infection in 34 (38.2%), mixed infection in 24 (27.0%), and non-infection in 31 (34.8%) cases. Concerning the single infection, C. albicans was the most predominant (58.8%), followed by C. parapsilosis (17.6%), C. glabrata (14.7%), C. tropicalis (5.9%), and C. krusei (2.9%). As for the mixed infection, the most frequent combination was C. albicans and C. glabrata (50.0%), followed by C. albicans and C. parapsilosis (29.2%), C. albicans and C. tropicalis (8.3%), C. glabrata and C. tropicalis (4.2%), C. albicans, C. glabrata, and C. parapsilosis (4.2%), and C. albicans, C. parapsilosis, and C. glabrata (4.2%). There were four MALDI-TOF MS positive results that were negative by the culture test. Conversely, there were six MALDI-TOF MS negative results that were positive by the culture test. The sensitivity and specificity of MALDI-TOF MS were 0.929 and 0.840, respectively. The concordance rate of genus Candida was 0.644, indicating substantial agreement. Conclusion: Candida infection is complicated by disease type and oral cavity environment changes due to aging. A rapid microorganism detection method, such as MALDI-TOF MS, will be helpful to quickly determine the causative pathogen in dental infections.