In this study, we aimed to clarify the phylogenetic distribution of Exophiala dermatitidis in Japan and describe the characteristics of genotypes. We examined 67 clinical and environmental isolates that were morphologically identified and preserved as E. dermatitidis and we confirmed the identification on the basis of the ribosomal DNA internal transcribed spacer region. Genotype sequences were aligned and compared using maximum likelihood phylogenetic tree analyses of the ITS1 region. Additionally, the strains of each genotype were tested for mycological characteristics, such as growth temperature, growth rate, and drug sensitivity. The 67 strains examined were isolated from Japan, the United States, Brazil, Venezuela, and China. In accordance with the establishment of a phylogenetic tree for the ITS1 region, 45 of the 49 Japanese strains were classified as genotype A, two as genotype B, and two as genotype D (A2 according to the method of Matos et al. (2003)). Chinese strains were divided into genotypes A and D (A2), and South American strains were classified into genotypes A, B, B2, and C2, while all strains from the U.S. belonged to genotype A. New genotype groups B2 and C2 were identified in Brazilian and Venezuelan strains, respectively. There were no specific differences among the genotypes or isolated regions in the antifungal susceptibility test for all E. dermatitidis isolates. However, genotypes B2 and D (A2) exhibited growth at higher temperatures than the other genotypes.
In clinical settings, the number of immune compromised patients have increased as a result of developments in medical technology (e.g., organ transplantation, anticancer drugs, steroids, TNF inhibitors, etc.). However, patients with fungal diseases are also increasing globally. In recent years, the distribution and pathogenicity of fungi worldwide have been changing, with reports that new fungi are emerging, and antifungal-resistant fungi are spreading globally. Global warming, globalization, human activities, and other factors have been suggested as contributing to the emergence of new fungi. Some of the antifungals against which resistant fungi have emerged are commonly used not only for human but also for animal health care and crop protection. Consequently, the occurrence of antifungal-resistant fungi has become a clinical issue. Solving these problems entails continuing the “One Health” approach, which in turn requires updating medical mycology information with regard to the emerging pathogenic fungi. In particular, this paper reviews the recent information on Cryptococcus gattii, Candia auris, and azole-resistant Aspergillus fumigatus.
The genus Prototheca consists of achlorophyllic algae that are ubiquitous in the environment and also occur in animal intestines; occasionally, infections in humans and animals are observed. In this study, we conducted tests of assimilative abilities and thermotolerance in comparison with morphological characteristics of six opportunistic species (Prototheca blaschkeae, Prototheca bovis, Prototheca ciferrii, Prototheca cutis, Prototheca miyajii, and Prototheca wickerhamii) along with Prototheca paracutis. Five of the seven species could be differentiated by physiological characteristics, but P. wickerhamii and P. cutis had identical profiles. Of the cattle-associated species, only P. bovis was able to grow at 42°C. Both type strains of P. cutis and P. miyajii were most susceptible to ravuconazole compared with the other azoles.
Nannizzia gypsea, previously known as Microsporum gypseum, is a geophilic dermatophyte that infects humans from the soil. We isolated N. gypsea from a two-year-old girl with kerion celsi. Because of her serious medical condition, she was admitted to the pediatric ward immediately after birth. We struggled to identify the route of infection, and eventually identified her grandmother’s handmade belt, which covered the endotracheal-tube-holding device, as the infection source. To prevent indirect transmission of pathogenic microorganisms from outside the hospital environment, our hospital prohibited the bringing of belongings from outside.