Aspergillus fumigatus, an opportunistic pathogenic fungus, is common in the environment. Azole-resistant strains of A. fumigatus have recently been discovered in the environment. Acquisition of azole resistance has been considered to occur through unexpected selection due to fungicide use in agriculture. This review discusses the relationships of humans with A. fumigatus in the environment and the importance of anthropogenic activities in the spread of A. fumigatus worldwide.
The prevalence of Trichophyton-induced superficial skin mycosis is very high among human patients. Dermatophytes generally infect the epidermis, especially the stratum corneum, forming scales, hyperkeratosis, and vesicles. The important roles played by the immune system in Trichophyton infection are detection of fungal invasion and elimination of fungi. These immune mechanisms are presumed to involve not only innate immunity but also acquired immunity. Therefore, there is a substantial need for studies on treatment methods based on new basic knowledge, and the elucidation of immunological mechanisms of Trichophyton-induced inflammatory reactions is especially important. However, since Trichophyton cannot colonize on the mouse skin, we tried to develop a model for Trichophyton inflammation induced by trichophytin extracted from Trichophyton mentagrophytes using a method based on contact hypersensitivity. Trichophytin is a crude extract that mainly contains fungal cell wall constituents including β-glucan and zymosan. In this model, TLR2, TLR4, and dectin-1 were highly expressed, and production of IL-17A and IL23 was observed. This indicates that we succeeded in inducing fungal-specific inflammation in the mice. In this review, we introduce a mouse Trichophyton inflammation model developed to investigate the immunological mechanisms of Trichophyton-induced inflammatory reactions. In addition, we report results of evaluation of anti-inflammatory and anti-itching effects of anti-fungal agents using the inflammation model.
Tinea pedis and tinea unguium are the most common dermatophytoses seen in the daily practice of dermatology. According to a report in Japan Foot Week 2006, it is estimated that about 1 in 5 Japanese have tinea pedis and that about 1 in 10 have tinea unguium. Thus far, use of oral antifungal agents has been the first-line therapy for onychomycosis. Many patients with onychomycosis, however, are elderly and have concomitant diseases as well as liver function disorder. Moreover, oral medications are reportedly associated with risks of impaired liver function and interactions. Due to such risks, therefore, treatment with topical agents is the only applicable therapy for most patients with onychomycosis. Recently, two topical agents (efinaconazole in 2014 and luliconazole in 2016) have been approved for the treatment of onychomycosis in Japan. Efinaconazole 10% solution is a triazole antifungal drug developed in Japan. Due to its low keratin affinity, efinaconazole shows high transungual penetration into nails and retains a high antifungal activity in the nail plate and the nail bed. Luliconazole 5% solution is an imidazole antifungal agent that has high keratin affinity. Luliconazole has also been shown in vitro to permeate from the superficial to the deep layers of the nail and to achieve concentrations above the MIC in all layers of the nail. Both efinaconazole 10% solution and luliconazole 5% solution have high antifungal activities for Trichophyton species. These two topical agents, therefore, have certainly increased treatment options for onychomycosis in the daily practice of dermatology.
We report here the results of the 2016 epidemiological survey of dermatomycosis in Japan. In total, 6,776 cases were analyzed as follows: dermatophytosis, 5,772 cases (85.2%); candidiasis, 757 cases (11.2%); Malassezia infection, 235 cases (3.5%); and other fungal infections, 11 cases (0.2%). In dermatophytosis, tinea pedis was the most frequent (3,314 cases: male, 1,705; female, 1,609), followed by tinea unguium (1,634 cases: male, 766; female, 868), tinea corporis (423 cases: male, 241; female, 182); tinea cruris (316 cases: male, 242; female, 74); tinea manuum (58 cases: male, 29; female, 29); tinea capitus, Celsus’ kerion (26 cases: male, 19; female, 7); and tinea barbae (1 case: male, 1). The most frequent pathogen was Trichophyton rubrum. In candidiasis, candidal intertrigo was the most frequent (181 cases: male, 98; female, 83), followed by oral candidiasis (165 cases: male, 84; female, 81), genital candidiasis (119 cases: male, 45; female, 74), diaper candidiasis (113 cases: male, 49; female, 64), erosio interdigitalis (63 cases: male, 13; female, 50), onychomycosis (41 cases: male, 17; female, 24), onychia et paronychia (28 cases: male, 2; female, 26), and angular cheilitis (23 cases: male, 6; female, 17). Although the number of cases varied depending on the role of each cooperating medical institution in the area and on population composition, no significant differences in the frequencies of clinical types were observed.