The Malassezia species are dimorphic fungi that require lipids such as olive oil for their growth. They are constituents of the normal human skin microbiota and can affix to the host or other surfaces through the establishment of biofilms. Malassezia species are accountable for superficial mycoses like folliculitis. Additionally, they are capable of causing invasive infections, such as of the bloodstream, in neonates and immunocompromised patients, albeit infrequently. Catheter-associated bloodstream infections in neonates are the most commonly reported invasive cases. Remarkably, unlike other invasive fungal infections, neutropenia and the use of broad-spectrum antibiotics do not seem to contribute to the risk of invasive Malassezia infections. Nosocomial outbreaks of Malassezia infections have been reported. While most cases of invasive Malassezia infection are fungemia, they seldom give rise to disseminated lesions in various organs. The diagnosis can be confirmed by the visualization of characteristic yeasts through histologic or cytologic examination of a biopsy or needle aspiration specimen, or via positive culture results from sterile sites. The prognosis for invasive Malassezia infection is generally favorable, with few reports of treatment failure. Nevertheless, due to the limited number of cases, evidence-based treatment recommendations are wanting. Management of invasive Malassezia infections linked to central venous catheters includes removal of the catheter, cessation of intravenous lipid emulsion, and intravenous administration of appropriate antifungal agents.

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This is a report of the results of the epidemiological survey on dermatomycoses conducted in 2021. A total of 9,442 patients with dermatomycosis were reported for one year. They include 8,151 (86.3%) with dermatophytosis, 796 (8.4%) with candidiasis, 484 (5.1%) with Malassezia infection, and 11 (0.1%) with deep cutaneous mycosis. In order, the most common types of dermatophytoses were tinea pedis (4,195 cases, 2,341 males and 1,854 females), tinea unguium (2,711 cases, 1,509 males and 1,202 females), tinea corporis (674 cases, 445 males and 229 females), tinea cruris (399 cases, 305 males and 94 females), tinea manus (125 cases, 78 males and 47 females), and tinea capitis (47 cases, 25 males and 22 females). The number of cases of tinea pedis and tinea unguium increased during the summer. A higher percentage of patients were aged 80 or older than in previous surveys. These findings may reflect the increasing percentage of elderly patients seen and the superannuation of the population. As in previous surveys, Trichophyton rubrum and Trichophyton interdigitale were the two most frequently isolated species of fungi causing dermatophytoses. Microsporum canis and Trichophyton tonsurans were the two species most often causing tinea capitis.
Regarding cutaneous candidiasis, while candidal intertrigo was the most common in previous surveys, diaper candidiasis in the elderly was the most common in this survey. A background check revealed that this was because a facility included a semi-prophylactic approach to address diaper candidiasis occurring within the ward.
Malassezia infections by Malassezia folliculitis clearly increased with each survey. The tendency of certain facilities with many reports of Malassezia folliculitis suggests that it is greatly affected by the presence of physicians familiar with the disease.

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Aspergillus species have been identified morphologically in most clinical laboratories without conducting antifungal susceptibility tests (ASTs). This review aimed to evaluate the importance of accurate identification and ASTs of Aspergillus spp. strains for adequate clinical management of Aspergillus infections. The Aspergillus spp. were identified by gene sequencing, and ASTs for itraconazole and voriconazole were conducted. In Aspergillus section Nigri, the rate of detection of cryptic species was high, and Aspergillus tubingensis with lower susceptibility to azoles was frequently identified. Azole-resistant Aspergillus fumigatus was detected at a high rate in patients with chronic pulmonary aspergillosis managed with long-term azole treatment. In conclusion, accurate identification of Aspergillus spp. and ASTs are needed to carry out appropriate treatment. Moreover, we hope that these microbiological tests will be widely used in clinical laboratories to improve clinical practice.

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Aspergillus udagawae is a cryptic species of Aspergillus section Fumigati. Here, we report a case of canaliculitis with isolated A. udagawae. Fungal canaliculitis is a rare lacrimal disease, and its clinical features are poorly understood. The causative fungus was initially misclassified as Aspergillus thermomutatus by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) but was finally identified as A. udagawae by β-tubulin genetic analysis. The patient showed rapid improvement and did not experience relapse after drainage alone, without antifungal therapy. A. udagawae has low virulence, which may be related to the minimally invasive nature of the infection.

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We conducted antifungal susceptibility testing on itraconazole (ITCZ)-resistant isolates of Trichophyton interdigitale and Trichophyton rubrum collected from Japanese patients in 2021 and 2022. The aim of the present study was to determine the most effective drug against ITCZ-resistant strains of dermatophytes. In all isolates, the minimum inhibitory concentrations (MICs) were > 32 mg/l for ITCZ, < 0.03 to 0.5 mg/l for ravuconazole (RVCZ), and < 0.03 mg/l for efinaconazole (EFCZ), luliconazole (LUCZ), and terbinafine (TRBF). Thus, in tinea unguium cases with ITCZ-resistant strains, treatment should be switched to TRBF or other azoles with a stronger antifungal efficacy, such as EFCZ, LUCZ, or RVCZ, and treatment must continue until the infectious organisms are completely eliminated.

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