ABSTRACT
The incidence of Malassezia species recovered from the external ear canal was characterized using culture medium optimized for Malassezia spp., CHROMagar Malassezia. The results of this study indicated that in healthy individuals M. slooffiae was the dominant Malassezia species followed by M. restricta.
Subject(s)
Carrier State/epidemiology , Carrier State/microbiology , Ear Canal/microbiology , Malassezia/isolation & purification , Adult , Culture Media/chemistry , Female , Humans , Incidence , Male , Middle Aged , Mycology/methodsABSTRACT
Malassezia-positive smears can be recognized from otitis externa, however, there are few references in the literature to the relation between Malassezia and otitis externa. Therefore, the bacterial and clinical characteristics of 72 cases (63 patients) with otitis externa were investigated at the Department of Otorhinolaryngology, Takinomiya General Hospital to analyze this. Thirty-seven cases were bacterial otitis externa, 20 cases were fungal otitis externa, and 15 cases were etiological agents unknown in this study. The causative organisms in fungal otitis externa were the genera Aspergillus (10 cases), Malassezia (5) and Candida (5), respectively. We suspected that 5 cases were caused by Malassezia because Malassezia cell counts were greater than 10 per field (x 400), and a large number of Malassezia were isolated from all cases. In these cases, many squamous epithelial cells were observed by direct examination, and cells from the middle or basal layer of the ear canal were also recognized in three cases. Therefore, accelerated turnover of epidermal cells of the ear canal was suggested. The main symptoms were itching and fullness in the ear, with observations of redness and erosion in objective deterioration, and we felt that these conditions were similar to seborrheic dermatitis (SD). In addition, these five cases were confirmed as fungus-related otitis externa by their improvement with antifungal agents.
Subject(s)
Malassezia/isolation & purification , Otitis Externa/microbiology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Dermatomycoses/microbiology , Female , Humans , Infant , Male , Middle AgedABSTRACT
Forty-six strains of Malassezia spp. with atypical biochemical features were isolated from 366 fresh clinical isolates from human subjects and dogs. Isolates obtained in this study included 2 (4.7%) lipid-dependent M. pachydermatis isolates; 1 (2.4%) precipitate-producing and 6 (14.6%) non-polyethoxylated castor oil (Cremophor EL)-assimilating M. furfur isolates; and 37 (34.3%) M. slooffiae isolates that were esculin hydrolyzing, 17 (15.7%) that were non-tolerant of growth at 40 degrees C, and 2 (1.9%) that assimilated polyethoxylated castor oil. Although their colony morphologies and sizes were characteristic on CHROMagar Malassezia medium (CHROM), all strains of M. furfur developed large pale pink and wrinkled colonies, and all strains of M. slooffiae developed small (<1 mm) pale pink colonies on CHROM. These atypical strains were distinguishable by the appearance of their colonies grown on CHROM. Three clinically important Malassezia species, M. globosa, M. restricta, and M. furfur, were correctly identified by their biochemical characteristics and colony morphologies. The results presented here indicate that our proposed identification system will be useful as a routine tool for the identification of clinically important Malassezia species in clinical laboratories.
