Utilization of matrix‐assisted laser desorption and ionization time‐of‐flight mass spectrometry for identification of infantile seborrheic dermatitis‐causing Malassezia and incidence of culture‐based cutaneous Malassezia microbiota of 1‐month‐old infants

Abstract

Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been utilized for identification of various microorganisms. Malassezia species, including Malassezia restricta, which is associated with seborrheic dermatitis, has been difficult to identify by traditional means. This study was performed to develop a system for identification of Malassezia species with MALDI-TOF-MS and to investigate the incidence and variety of cutaneous Malassezia microbiota of 1-month-old infants using this technique. A Malassezia species-specific MALDI-TOF-MS database was developed from eight standard strains, and the availability of this system was assessed using 54 clinical strains isolated from the skin of 1-month-old infants. Clinical isolates were cultured initially on CHROMagar Malassezia growth medium, and the 28S ribosomal DNA (D1/D2) sequence was analyzed for confirmatory identification. Using this database, we detected and analyzed Malassezia species in 68% and 44% of infants with and without infantile seborrheic dermatitis, respectively. The results of MALDI-TOF-MS analysis were consistent with those of rDNA sequencing identification (100% accuracy rate). To our knowledge, this is the first report of a MALDI-TOF-MS database for major skin pathogenic Malassezia species. This system is an easy, rapid and reliable method for identification of Malassezia.

Performance of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identifying Clinical Malassezia Isolates

“…These results differ from those published by Kolecka et al (24), who succeeded in building a MALDI-TOF database for identifying Malassezia yeasts from strains cultivated on Dixon medium, possibly due to the use of another mass spectrometer. A second Malassezia database built and tested by another group (25) was obtained from cultures grown on CHROMagar Malassezia medium, which contains glycerol and a low proportion of Tween 60. Furthermore, modification of the quantities of formic acid and acetonitrile during the extraction procedure was revealed to be crucial to obtaining interpretable spectra.…”

“…These results are comparable with those of the other two databases published recently. The first, developed by Kolecka et al (24), included 14 species (48 strains) and identified 84.8% of the strains tested, whereas the latter, from Yamamoto et al (25), contained 8 species (18 strains) and identified 92.8% of the unknown strains with a log score value between 1.7 and 2.0. Although our database currently contains only six species, it remains representative of the local epidemiology of Malassezia yeasts in France.…”

Malassezia infections with systemic involvement: Figures and facts

“…30 Furthermore, the non-uniformity in the culture media used may be another important issue when interpreting the results. 30,35 Susceptibility profile and treatment Therapy of Malassezia bloodstream infections is mainly based on previous experience and antifungal susceptibility data. Susceptibility testing has not been standardized for these yeasts and therefore is not performed by routine in many clinical laboratories.…”

Malassezia species and their associated skin diseases

“…Recently, matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS), mainly developed by Japanese engineers, has become the state‐of‐the‐art procedure in medical or biological research. Several studies demonstrated the value of MALDI‐TOF‐MS as an intensive identification system for Malassezia isolates …”

“…Several studies demonstrated the value of MALDI-TOF-MS as an intensive identification system for Malassezia isolates. 13,14 Since the early 2000s, the culture-independent and PCRbased methods described above have been employed for analyses of the human microbiota of microorganisms including viruses, bacteria and fungi. [15][16][17] Moreover, these methods enabled direct detection of the Malassezia microbiota in normal skin as well as in lesional skin of PV, SD or AD patients.…”