TITLE:
Comparative Study of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry and Culture Test for Candida Identification
AUTHORS:
Yoriko Kubota, Chieko Taguchi, Masanori Saito, Noriko Shinozaki-Kuwahara, Tomoko Suzuki, Masaaki Suemitsu, Mitsuko Nakayama, Tadahiko Utsunomiya, Hiroyasu Endo, Kayo Kuyama
KEYWORDS:
Candida, Culture Test, MALDI-TOF MS, Non-C. Albicans Candida (NCAC)
JOURNAL NAME:
Open Journal of Stomatology,
Vol.9 No.12,
December
17,
2019
ABSTRACT: 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.