To date, no reliable biological clock markers have been identified to elucidate the phylogenetic relationships among the three species within the Trichophyton mentagrophytes complex-namely T. interdigitale, T. mentagrophytes, and T. indotineae. This study, employing a polyphasic approach, confirmed that 62 clinical isolates of the T. mentagrophytes complex obtained from Guizhou tend to cluster into two distinct groups: Group I (42 isolates, comprising T. interdigitale and T. indotineae) and Group II (20 isolates, representing T. mentagrophytes). These groups exhibited statistically significant differences in molecular characteristics, phenotypic traits, MAT locus distribution, clinical pathogenicity, and antifungal susceptibility profiles. Notably, the identification of a cryptic sexual state in T. interdigitale revealed unexpected genetic affinities between the two groups. In particular, the hybrid strain JYP 23487, classified as T. mentagrophytes, and its granular variant JYP 23487k, which occupies an intermediate position in the MAT1-1 gene phylogenetic tree (MAT1-1-1 genotype C), provide evidence for genetic continuity and suggest a potential link between fungal morphological variation and mating type gene composition. Collectively, the Guizhou isolates of the T. mentagrophytes complex demonstrate a dynamic pattern of genetic continuity and shared MAT genotypes that correlate with phenotypic traits, providing additional evidence for the blurred taxonomic boundaries between the traditionally defined species T. interdigitale and T. mentagrophytes. The occurrence of strains with dual mating type loci or intermediate genotypes may be attributed to frequent host switching, facilitating recombination and exchange of MAT gene regions.

The epidemiology of sporotrichosis, a neglected mycosis caused by Sporothrix species, has shifted in South America from classic sapronosis to urban zoonosis driven by feline transmission of the hypervirulent Sporothrix brasiliensis. However, the fine-scale transmission dynamics of this epidemic, particularly within households, remain poorly understood. Here, we dissect an intrafamilial outbreak in Brazil involving a cat (the index case), a dog, and three humans. High-resolution genotyping using 15 microsatellite markers revealed a clonal transmission event, with isolates from the index cat and human patients being genetically indistinguishable (100% similarity). Multiple bioinformatic analyses, including principal component analysis, minimum spanning tree, and self-organizing maps, corroborated these findings. Strikingly, this outbreak strain produced markedly divergent clinical phenotypes, including Parinaud’s oculoglandular syndrome in an 8-year-old girl, a fixed cutaneous lesion in her 5-year-old brother, and a disseminated maculopapular exanthem in her 28-year-old mother. This clinical pleomorphism from a genetically invariant pathogen unequivocally demonstrates the pivotal role of host factors, such as age, immune response, and inoculation site, in dictating disease manifestation. Furthermore, all outbreak isolates belonged to the MAT1-1 idiomorph, a finding that challenges the paradigm of a monolithic epidemic dominated by MAT1-2 strains and suggests a more complex, polycentric expansion of S. brasiliensis. Overall, this study provides strong evidence of zoonotic transmission and highlights how host determinants, not pathogen variability, shape the clinical diversity of sporotrichosis.

BackgroundAntifungal susceptibility testing (AFST) guides therapy for invasive and refractory fungal infections, but routine testing of species with predictable, species-level (intrinsic) resistance can waste laboratory resources.MethodsNarrative synthesis of guideline documents and recent literature to define intrinsic resistance, summarize major fungal examples, and propose a selective AFST framework.ResultsKey taxa show intrinsic non-susceptibility (e.g., Pichia kudriavzevii to fluconazole; Mucorales to short-tailed azoles; Cryptococcus spp. to echinocandins). Terminology differences between EUCAST and CLSI are noted. Recommended AFST is targeted to invasive/rare pathogens, treatment failure, surveillance, outbreak investigation, and evaluation of novel agents.ConclusionA selective AFST strategy, reserving routine testing for species with variable or emergent resistance, enhances laboratory efficiency and antifungal stewardship while ensuring appropriate clinical therapy.

Candida tropicalis frequently causes invasive infections in immunocompromised hosts. Mortality rates are high compared to other yeasts, while antifungal resistance varies between countries. To date, multicenter studies regarding C. tropicalis infections in Türkiye are limited. The current study therefore characterized C. tropicalis infections in Türkiye. In this retrospective study, 120 invasive C. tropicalis isolates were collected from four hospitals in Türkiye, mostly from blood. In vitro antifungal susceptibility testing (AFST) was performed for eight common antifungals, and short tandem repeat (STR) genotyping was applied to investigate genetic relatedness within the current population and previously genotyped isolates. Patients with invasive C. tropicalis candidiasis were mostly elderly, with a central venous line (CVL) and cancer or diabetes as underlying disease, and an overall mortality rate of 37%. Except for a single isolate from blood being resistant to fluconazole and voriconazole, no resistance to common antifungals was found. Finally, nosocomial transmission within hospitals was limited as nearly all isolates displayed unique genotypes. When compared to 605 previously investigated isolates from 12 diverse countries, only few clusters were present, indicating an overall high genetic diversity for C. tropicalis. While isolates from the current study did not form a single monophyletic branch, there were 27 isolates that formed a distinct pan-susceptible clade together with isolates of other Middle Eastern countries. To conclude, we described a retrospective multicenter study on invasive C. tropicalis infections in Türkiye characterized by a high mortality rate for untreated patients, while isolates showed little antifungal resistance and high genetic diversity.

The antifungal armamentarium is shrinking while resistance to licensed agents rises. Historically, actinomycetes and fungi delivered nystatin, amphotericin B, griseofulvin and the echinocandin scaffold, yet plant-derived compounds-despite potent in-vitro activity-have rarely reached the clinic. To frame the recent in-vivo success of papaya-seed essential oil against fluconazole-sensitive and -resistant Candida albicans within the broader context of plant-based antifungal discovery, and to propose rigorous criteria that can accelerate translation, especially considering varying resource settings. Commentary on Ma et al. (Mycopathologia 190(5):1-14, 2025) showing that benzyl-isothiocyanate-rich papaya-seed oil outperforms fluconazole in a murine systemic candidiasis model without acute toxicity; Historical perspective on how soil microbes provided the first broad-spectrum antifungals; An eight-point checklist for future plant-extract studies, with essential and suggested elements to promote high-quality research across different laboratory settings. Adherence to core methodological standards, along with suggested advanced analyses where feasible, will help identify promising plant-derived antifungal leads and support a more inclusive and effective discovery pipeline.

Aspergillus section Flavi comprises opportunistic pathogens such as Aspergillus flavus, posing significant health risks. Unlike A. fumigatus, where environmental selection drives widespread resistance, it is uncertain whether A. flavus develops azole resistance through a similar environmental route. This study analyzed 544 Aspergillus section Flavi isolates collected from 534 patients in Dutch hospitals (1994-2023). Calmodulin sequencing was used for molecular identification. Antifungal susceptibility testing (AFST) was performed according to EUCAST (European Committee on Antimicrobial Susceptibility Testing) guidelines. Cyp51A was sequenced and mutations were mapped onto the CYP 51 protein 3D model for azole-resistant or non-wild-type isolates. Clinical data, including azole exposure history and underlying diseases, were correlated with the resistance profiles. Of the 544 isolates, 520 were identified as A. flavus and 24 as related species, including A. tamarii (16), A. parasiticus (3), A. nomiae (2), A. pseudonomiae (2), and A. pseudocaelatus (1). Fourteen isolates from five patients were azole-resistant/non-WT, with resistance rates ranging from 0.2 to 0.8%. Resistant/non-WT isolates were associated with chronic diseases and prior clinical azole exposure. Among 10 patients with proven/probable invasive aspergillosis azole resistance was not observed. Two main Cyp51A-SNPs were found in azole-resistant isolates: Y119F and T329A. Aspergillus flavus was the dominant pathogenic species within the section Flavi with low levels of azole resistance. Distribution of resistant cases supports in host resistance selection rather than environmental selection. These findings highlight the need for further research on the ecological and molecular factors that influence resistance in A. flavus.

BackgroundThe escalating threat of antifungal resistance stemming from Trichosporon asahii (T. asahii) biofilms necessitates the pursuit of innovative therapeutic strategies. Among these approaches, 5-aminolevulinic acid (ALA) photodynamic therapy (PDT), an emerging therapeutic modality, has exhibited promising potential in eradicating T. asahii biofilms.MethodsThe inhibitory activity was evaluated by confocal laser scanning microscopy. To delve deeper into the efficacy of ALA-PDT in eliminating T. asahii biofilms, we conducted a comprehensive transcriptional analysis utilizing transcriptome sequencing.ResultsALA-PDT demonstrated a profound inhibitory effect on the viability of T. asahii biofilms. Our investigation unveiled 2720 differentially expressed genes following exposure to ALA-PDT. Subsequent meticulous scrutiny allowed for the annotation of genes with a ≥ twofold change in transcription, focusing on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. Particularly noteworthy were the upregulated genes associated with oxidation–reduction processes, oxidoreductase activity, and catalytic activity. Conversely, the downregulated genes were linked to ATP binding, protein phosphorylation, and protein kinase activity. Additionally, we observed a surge in the transcription of genes that may be involved in oxidative stress (e.g., A1Q1_05494) as well as genes that may be involved in morphogenesis and biofilm formation (e.g., A1Q1_04029, A1Q1_01345, A1Q1_08069, and A1Q1_01456) following ALA-PDT treatment.ConclusionsOur findings underscore the substantial impact of ALA-PDT on the transcriptional regulation of genes related to oxidative stress, morphogenesis, and biofilm formation, paving the way for novel therapeutic avenues in combating T. asahii biofilms.

Interdigital tinea pedis is a common type of tinea pedis that occurs between toes and is easy to recur. Recently, the skin microbiome analysis of interdigital tinea pedis showed changes in bacterial microbiome in addition to fungal infection. To investigate the efficacy and safety of clioquinol 3% cream in treating interdigital tinea pedis as well as characterize changes in the skin microbiome during treatment. The clinical characteristics and skin microbiome of patients with interdigital tinea pedis were investigated in a longitudinal prospective study. In total 28 participants were rcruited to use the clioquinol 3% cream topically to the target skin lesions twice a day for 1week. Disease severity evaluation, fungal microscopic examination, and sample collection for skin microbiome analysis were performed at baseline, after treatment, and 1week post-treatment. Compared with baseline, the disease severity, lesion score, pruritus score, and malodor score of the patients significantly decreased after treatment and at 1week post-treatment (P < 0.05). The fungal profiles after treatment and 1week post-treatment revealed significantly decreased abundance of Trichophyton and significantly increased abundances of Cladosporium, Alternaria, and Aspergillus, which led to higher fungal diversity than pretreatment samples. The bacterial profiles after treatment and 1week post-treatment revealed significantly decreased abundances of Brevibacterium, Finegoldia, and Facklamia. The abundance of Streptococcus and bacterial diversity were also significantly decreased at 1week post-treatment. The disease severity was positively associated with the abundance of Trichophyton, Arthroderma, Finegoldia, Facklamia, Brevibacterium, Corynebacterium, and Porphyromonas. The clioquinol 3% cream was efficient on treating interdigital tinea pedis by decreasing the abundance of pathogenic fungus, recovering the normal balance of the fungal and bacterial communities, and restore species diversity.