การเหนี่ยวนำการสร้างสายราในหลอดทดลองของเชื้อ Malassezia species ที่แยกได้จากผู้ป่วยโรคเกลื้อนและผู้มีสุขภาพดี

Abstract

Malassezia spp. are lipophilic yeasts that consider as part of normal flora organisms of human skin. It has been associated with various human skin diseases, especially pityriasis versicolor (PV). Malassezia spp. were isolated from 15 patients with PV and 165 healthy volunteers. Malassezia spp. were differentiated by using biochemical test and PCR amplification. From the correlation results of these two methods, 70.56% (127/180) of agreement was found in species identification of Malassezia resulted in M. furfur (46.45%), M. sympodialis (46.45%), M. dermatis (3.94%) and M. slooffiae (3.15%). In addition, 53 isolates of Malassezia spp. were differentiated by PCR amplification only and then confirmed by nucleotide sequence analysis. Totally, 180 isolates of Malassezia spp were identified into 6 species including M. furfur (42.79%), M. sympodialis (42.22%), M. dermatis (8.33%), M. slooffiae (3.33%), M. globosa (2.22%) and M. japonica (1.11%). Only M. furfur (73.33%) and M. globosa (26.67%) were isolated from lesional skin of PV. In addition, Malassezia spp. isolated from skin of healthy volunteers were identified as M. sympodialis (46.06%), M. furfur (40.00%), following by M. dermatis (9.09%), M. slooffiae (3.64%) and M. japonica (1.21%). This finding suggested that PCR method can be used as a potential tool for the species identification of Malassezia spp. when compared with the biochemical method. The result of filament induction in vitro revealed that only 48% (37/77) of M. furfur was able to produce the mycelial but not found in other species of Malassezia. The conditions that induced M. furfur to synthesis hyphae were classified into 3 groups: Minimal medium (MM) with L-DOPA and kojic acid, MM with L-DOPA, and MM only. In total, 83.78% (31/37) different isolates of M. furfur was able to produce the hyphae when grown on MM with L-DOPA and kojic acid. The protein profile of M. furfur yeast and mycelial form was compared. It revealed that protein bands of 41 and 48 kDa were more expressed in the yeast form than in the mycelial form. The difference of these proteins expression will need more studies. It may probably be involved in the pathogenesis of this fungus.