Mycopathologia最新文献

The ability to survive and militate oxidative stress has received particular attention as one of the virulence factors of human pathogens. While underlying mechanisms have been largely studied for some fungi, those employed by the rising opportunistic fungal threat Scedosporium spp. are not fully understood yet. Previous transcriptomic studies helped identify the main oxidative stress-induced antioxidant enzymes in S. apiospermum. We therefore wanted to gain insight into regulators governing this response. We aimed to generate and characterize a knock-out mutant of S. apiospermum lacking the SKN7 gene, which encodes one of the main regulators of response to oxidative stress in fungi. The skn7Δ mutant was multifacetedly characterized on phenotypic and transcriptomic levels. Findings support pertinent roles of S. apiospermum Skn7 protein in protection against different types of oxidative stress, mainly cumene hydroperoxide and diamide. Skn7 was also protective against stress-induced accumulation of reactive oxygen species (ROS), as well as macrophage-mediated killing. This protection is likely mediated by the upregulation of genes encoding components of the thioredoxin and peroxiredoxin systems, which exhibit dependency on Skn7. Furthermore, we demonstrated a potential role of Skn7 in the synthesis of the hyphal cell wall. In conclusion, the response regulator Skn7 plays an essential role in protecting S. apiospermum against oxidative threat, whether generated by chemicals or by immune cells. Understanding the regulatory role of fungal Skn7 may help advance therapeutic strategies in combating fungal infections.

Background: Homozygous mutations in the Caspase-associated recruitment domain 9 (CARD9) gene increase susceptibility to invasive fungal infections, particularly those caused by Candida species. This study aims to assess the spectrum of CARD9 gene mutations that predispose individuals in the Turkish population, especially children, to invasive fungal infections.

Methods: Our study included 30 patients who were admitted to Ege University due to invasive fungal infection or chronic mucocutaneous candidiasis between 2020 and 2023. Demographic and clinical data of the patients were recorded, and a sequence analysis of the CARD9 gene was performed.

Results: The median age of the patients was 1.8 years (interquartile range [IQR]: 11.8). Diagnoses included fungal endocarditis (n = 8, 26.6%), chronic mucocutaneous candidiasis (n = 7,23.3%), central nervous system (CNS) infections (n = 6,20%), candidemia (n = 4,13.3%), fungus ball in the kidney (n = 2, 6.7%), endophthalmitis ( n = 1, 3.3%), concurrent CNS and intra-abdominal infection (n = 1, 3.3%), and concurrent CNS infection and endophthalmitis (n = 1, 3.3%). All 12 exons and exon-intron junctions of the CARD9 (NM_052813.5) gene that encodes the CARD9 protein were analyzed. A disease-causing variant was detected in 2 patients (6.6%). One patient had a Pseudallescheria boydii brain abscess, and the other had an invasive fungal infection confirmed histopathologically.

Conclusions: Among the 30 patients with invasive fungal infections, a disease-causing CARD9 mutation was identified in 2 (6.6%) patients. While CARD9 mutations are known to be associated with invasive candidiasis, this study reports the first pediatric case of P. boydii infection associated with a CARD9 mutation.

Sporotrichosis, a globally distributed subcutaneous mycosis, finds its most virulent agent in the species Sporothrix brasiliensis, particularly in zoonotic outbreaks associated with cats. This study investigated the role of aspartic proteases (APs) as potential virulence factors in S. brasiliensis. Through in silico analysis, we identified and characterized 19 genes encoding putative aspartic proteases in the S. brasiliensis genome. Susceptibility assays to different stressors demonstrated distinct profiles between the Sb1168 and Sb5110 strains, but the presence of Pepstatin A strongly inhibited growth under stress, indicating a crucial role for these enzymes in environmental adaptation. Proteolytic activity was modulated by cell wall stressors. Strain Sb1168 showed higher aspartic protease activity (87% inhibition by pepstatin A), while Sb5110 exhibited a mixed enzymatic profile, with significant contributions from metalloproteases (50% inhibition by EDTA and pepstatin A individually, and 80% in combination). Inhibition of APs blocked the mycelium-to-yeast (M → Y) dimorphic transition, suggesting that these proteases are dimorphism regulators. In macrophage assays, APs inhibition resulted in a significant increase in the phagocytic index and a reduction in intracellular fungal viability (CFU count), in addition to altering the profile of secreted cytokines (increase in pro-inflammatory IL-12 and decrease in anti-inflammatory IL-10 in treated Sb1168), suggesting these enzymes modulate immune evasion.

Background: Therapeutic drug monitoring (TDM) of itraconazole (ITC) has been recommended by international guidelines to optimize efficacy and reduce toxicity, especially in the context of invasive fungal infections. However, whether the same therapeutic targets apply to paracoccidioidomycosis (PCM) remains uncertain.

Methods: We conducted a retrospective analysis of patients with proven or probable PCM who used ITC during antifungal treatment between 2016 and 2024 at the University of São Paulo. Two groups were formed: the TDM group and the non-TDM group. Serum samples were obtained at steady-state (≥ 7 days after treatment initiation), and ITC levels were measured by liquid chromatography-mass spectrometry (LC-MS/MS). The institutional standard treatment was ITC capsules at 200 mg once or twice daily, depending on disease severity. Therapeutic serum trough concentrations were defined as 0.5-4.0 mg/L.

Results: Eighty-three patients were included, 18 in the TDM group and 65 in the non-TDM group, predominantly middle-aged males (median age 53 years; 70% male) with the chronic form of PCM (84%). Only 44.4% of initial serum concentrations were within the therapeutic range. Notably, 22% of patients had undetectable serum levels (< 0.014 mg/L). The median ITC concentration was 0.26 mg/L (IQR 0.04-1.95), and no toxic levels were observed. No statistically significant differences were found between the groups regarding ITC dose modification, drug interactions, toxicity, or duration of therapy.

Conclusion: Subtherapeutic serum ITC concentrations were common among PCM patients receiving capsule formulations. Although clinical response was generally favorable, the high variability in absorption highlights the potential value of TDM in selected cases. Prospective studies are warranted to define optimal target levels for PCM management.

Increasing attention has been given to the Trichophyton mentagrophytes complex as an agent of dermatophytosis. Despite technical challenges in differentiating lineages within this complex-which necessitates genotyping of the internal transcribed spacer (ITS) region-surveillance efforts are warranted due to the emergence of novel pathogens and rise in antifungal resistance. In North America, although studies have examined the molecular epidemiology of the T. mentagrophytes complex isolated from skin, there is scant information regarding this complex for the onychomycosis population. In this study, 516 clinical nail specimens were subjected to multiplex real-time PCR detection of the T. mentagrophytes complex followed by genotyping of the ITS1-5.8S-ITS2 region; squalene epoxidase (SQLE) gene mutations were also detected. All specimens were identified as T. mentagrophytes var. interdigitale belonging to one of five ITS genotypes (I, II, XI, XXIX, XXX). Genotype II was the most common (76% [392/516]) followed by genotype I (2.1% [11/516]), genotype XI (0.6% [3/516]), genotype XXIX (0.4% [2/516]) and genotype XXX (0.2% [1/516]). Notably, ITS genotypes XXIX and XXX are newly confirmed genotypes, which demonstrated stability and capacity for human-to-human transmission, evidenced by their earlier report and isolation in Australia. SQLE mutations, in particular Leu393Phe and Phe397Leu, were detected in ITS genotypes I and II, reflecting a higher risk of acquiring terbinafine resistance. The findings of this study serve to update our current understanding of the T. mentagrophytes complex.

Invasive candidiasis is a serious infectious disease that affects 2-10% of patients in the intensive care unit. It is caused by fungi of the genus Candida, and its diagnosis relies on multiple complex laboratory methods. Blood culture remains the gold standard for yeast detection in the bloodstream but has limited clinical utility because of its low sensitivity and prolonged turnaround time. Newer diagnostic approaches, such as molecular methods for Candida spp. DNA detection, which enable faster identificationbut still entail limitations, including variability in sensitivity. Another valuable tool is the detection of (1,3)-β-D-glucan, a polysaccharide in yeast cell walls; however, this marker lacks specificity. Timely initiation of appropriate antifungal therapy is crucial because delayed treatment is associated with increased mortality. Preventive strategies, including strict hygiene protocols and antifungal stewardship programs, are vital to reducing the incidence of invasive candidiasis. Emerging research on siderophores as candidate biomarkers for fungal infections indicates promising diagnostic potential. Given the complex pathogenesis and diverse clinical manifestations of invasive candidiasis, multifaceted diagnostic and therapeutic approaches are required. A combination of novel biomarkers, rapid molecular diagnostics, and optimized treatment strategies is essential to improve patient outcomes and reduce the complications associated with this life-threatening infection.

Neurocryptococcosis is a serious disease that mainly affects individuals with compromised immune systems. However, "immunocompetent" individuals are also affected by this condition even without any known underlying disease or compromised immune system. In this study, we evaluated the CD4 + T lymphocyte population and subpopulations in the peripheral blood of eight hospitalized patients with neurocryptococcosis and eight healthy control individuals. Thus, our objective was to contribute to this understanding by characterizing the T lymphocyte population (CD3 + CD4 +) and subpopulations, with analyses of the activation and regulation status of responsive T cells in naïve (N), central memory (TMC), effector memory (TME), and terminally differentiated effector (TEMRA) in apparently immunocompetent patients and healthy control individuals. Our results showed a significant increase in CD4 + γδ T subpopulations, CD4 + CD25 + CD127^low, CD4 + CD25 + CD127^+high regulatory T cells, CD4 + CD45RA + CCR7- terminally differentiated effector memory (TEMRA) T cells, and CD4 + CD45RA-CCR7- effector memory (TME) T cells. We also observed a significant decrease in total lymphocytes, CD4 + CD45RA + CCR7 + (naïve) T cells, and CD4 + CD45RA-CCR7 + central memory (TMC) T cells. CD4 + T and CD4 + αβ T cells did not show statistically significant differences between the study groups. These results suggest that the immune response of these patients is undergoing alterations in the maturation and differentiation of T lymphocytes and may be related to the virulence factors of the fungus that interfere in several mechanisms of the cells of both the innate and adaptive immune response, as well as with possible regulation disorders of T helper subsets immune responses during Cryptococcus infection.

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.

Paracoccidioidomycosis (PCM) is a severe systemic mycosis classified as a neglected disease, predominantly found in South America, with Brazil reporting the highest number of cases. In children and adolescents, PCM primarily manifests as an acute/subacute (juvenile) form. This systematic review focused on PCM cases in individuals under 15 years of age, analyzing 163 reports published between 1970 and 2023. The literature search was conducted across LILACS, SciELO, and PubMed databases using DeCS and MeSH descriptors in Portuguese, English, and Spanish.Most cases (70%) occurred in Brazil, followed by Argentina, Peru, Venezuela, and Colombia. The mean age was 8.4 years, with a male predominance (63%) and a median diagnostic delay of six months, reflecting underreporting and late disease recognition. The predominant clinical presentation was the disseminated form (90%), with generalized lymphadenopathy as the most frequent manifestation. Common symptoms included fever (66%), weight loss (54%), hepatomegaly (30%), and splenomegaly (25%). Severe complications such as lymph node fistulization (27%) and bone involvement (16%) were associated with poorer prognosis.Among the cases, 53% were classified as severe, frequently exhibiting marked eosinophilia (> 25,000 cells/mm³), ascites, and visceral involvement. Seven fatalities (5%) were recorded, strongly associated with hepatosplenomegaly (86% of fatalities vs. 22% of survivors), significant eosinophilia (71% vs. 15%), and rapid diagnosis (< 3 months). A predictive model combining these factors achieved 85.7% sensitivity and 92.3% specificity for mortality. Regarding therapy, combined antifungal regimens (e.g., amphotericin B plus itraconazole) achieved a 25% cure rate, while monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) was associated with 49% of fatalities.Pediatric PCM remains a neglected and highly lethal disease in severe forms. Early diagnosis, appropriate therapeutic combinations, and monitoring of clinical-laboratory markers with accurate classification are crucial for improved outcomes. The absence of detailed data in 34% of cases highlights gaps in clinical records, underscoring the need for prospective studies and standardization of severity criteria.