Comparative Study of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry and Culture Test for &amp;lt;i&amp;gt;Candida&amp;lt;/i&amp;gt; Identification

Yoriko Kubota,Hiroyasu Endo,Masaaki Suemitsu,Chieko Taguchi,Tadahiko Utsunomiya,Tomoko Suzuki,Masanori Saito,Mitsuko Nakayama,Noriko Shinozaki-Kuwahara,Kayo Kuyama

doi:10.4236/ojst.2019.912030

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.

Highlights

Candida is a large genus of ascomycetous yeast, consisting of about 150 species, and more than 20 species have clinical importance [1]
Specimens were immediately inoculated onto selective medium for CHROMagarTM Candida, and were carried out using MALDI-TOF MS
Candida infection is complicated by disease type and oral cavity environment changes due to aging

Summary

Introduction

Candida is a large genus of ascomycetous yeast, consisting of about 150 species, and more than 20 species have clinical importance [1]. C. albicans is a well-known colonizer and pathogen of the oral mucosa, non-C. albicans Candida (NCAC) is increasingly encountered [7] [8] [9] and its emerging role in human infections has gained attention [10] [11]. This rising number in infections caused by NCAC species may reflect both the improvement in diagnostic methodologies and the superior capability of NCAC species to persist in the host compared with C. albicans. A rapid microorganism detection method, such as MALDI-TOF MS, will be helpful to quickly determine the causative pathogen in dental infections

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Conclusion