Érica Simplício de Souza

Background: Cryptococcosis remains a severe systemic mycosis, especially among people living with HIV/AIDS, and culture-based molecular data from Amazonas remain limited. Objectives: The aim was to identify which Cryptococcus molecular types circulated among clinical isolates from Amazonas between 2020 and 2024; what were the main clinical characteristics and outcomes of patients infected with Cryptococcus neoformans molecular type VNI and Cryptococcus gattii molecular type VGII; and whether these molecular types differed in selected susceptibility-related and virulence-associated phenotypes. Methods: We analyzed 70 culture-confirmed clinical isolates from patients treated at the Dr. Heitor Vieira Dourado Tropical Medicine Foundation, Manaus, Brazil. Molecular types were assigned by URA5 PCR-RFLP using reference strains. Demographic and clinical variables were retrieved from medical records. A stratified 30-isolate subset comprising 24 VNI and 6 VGII isolates was evaluated for phospholipase activity and melanization. Fluconazole MICs were analyzed for the complete 70-isolate dataset and were determined by broth microdilution according to CLSI M27-A4. Results: VNI predominated (64/70; 91.4%), whereas VGII accounted for 6/70 isolates (8.6%). The series was predominantly composed of men, young adults, and HIV-positive patients. HIV infection was more frequent among VNI cases, whereas VGII included proportionally more HIV-negative patients. In-hospital death occurred in 17/70 patients (24.3%). Fluconazole MICs, phospholipase activity, and melanization were broadly comparable between VNI and VGII, although the small VGII subgroup precluded robust genotype-associated inference. Conclusion: VNI was the dominant molecular type in this severe reference-center cryptococcosis series from Amazonas. Phenotypic findings should be interpreted as exploratory and hypothesis-generating.

Cryptococcosis is a severe systemic mycosis, and relapse may be influenced by fungal subpopulations that survive fluconazole exposure. This retrospective cohort study investigated whether fluconazole minimum inhibitory concentration (MIC) and the heteroresistant (HetR) phenotype of the first available diagnostic cerebrospinal-fluid isolate were associated with recorded relapse within 6 months in 70 patients with neurocryptococcosis from Amazonas, Brazil. One clinical isolate per patient, comprising 64 Cryptococcus neoformans molecular type VNI and 6 Cryptococcus gattii molecular type VGII isolates, was evaluated by broth microdilution and endpoint-based fluconazole heteroresistance level (HFL) testing. Using an operational criterion of HFL/MIC ≥ 8, corresponding to visible growth at least three twofold dilutions above the MIC, 43 of 70 isolates (61.4%) were classified as displaying a HetR phenotype. Six-month follow-up was available for 69 patients. Recorded relapse occurred in 12 of 42 patients infected with HetR isolates (28.6%) and in 4 of 27 patients infected with non-HetR isolates (14.8%). Although relapse was numerically more frequent in the HetR group, the association was not statistically significant (conditional odds ratio, 2.27; exact 95% confidence interval, 0.59–10.96; two-sided Fisher’s exact test, P = .248). The HFL/MIC ratio also did not differ significantly according to recorded relapse status (P = .165). The HetR phenotype of the first available diagnostic isolate, defined operationally in this study as HFL/MIC ≥ 8, was frequent but was not significantly associated with recorded relapse within 6 months in this cohort.

Cultivable fungi are important components of freshwater ecosystems, yet their diversity in Amazonian aquatic environments remains poorly explored. This study evaluated cultivable fungal communities associated with water, sediment, and submerged wood in the Negro, Solimões, and Tapajós Rivers, representing the major black-, white-, and clear-water systems of the Amazon basin, respectively. Samples were collected along 25 m transects, fungi were isolated on potato dextrose agar, grouped into morphotypes, and identified morphologically. Diversity was assessed using richness, Shannon, Simpson, Pielou, and Sørensen indices. Overall, 130 isolates and 75 morphotypes were recorded, with a predominance of morphotypes assigned to filamentous Ascomycota and widespread occurrence of Aspergillus and Penicillium. Solid substrates yielded greater fungal abundance and richness than water samples. Submerged wood from the Negro River showed the highest overall cultivable fungal abundance, whereas the Tapajós River showed the highest diversity in water and sediment and the highest richness in both substrates. The Solimões River showed stronger dominance by a limited number of morphotypes, particularly in submerged wood. Sørensen similarity values indicated low compositional overlap among rivers, especially for submerged wood communities, suggesting apparent differentiation among river-associated cultivable fungal assemblages. Together, these exploratory results suggest that substrate type, hydrochemical differences, and potential temporal effects may be associated with the structure of cultivable fungal communities in Amazonian rivers.

The Amazon Forest harbors one of the largest fungal diversities on the planet, occupying a wide variety of ecological niches comprising terra firme (non-flooded forest), várzea (white-water floodplains), and igapó (black-water floodplains). In this review article, we examine Amazonian fungal diversity based on three complementary approaches—culture-based surveys, in situ inventories of macrofungi, and environmental DNA/metagenomic analyses—discussing advances, limitations, and contributions to regional mycological knowledge. Subsequently, we present a critical synthesis of the potential of Amazonian basidiomycetes regarding the production of metabolites with antimicrobial activity, highlighting the main genera reported in the literature, the chemical classes involved (e.g., terpenes, steroids, quinones, and bioactive peptides), and the metabolic pathways responsible for their biosynthesis. The integration between biodiversity and bioprospecting underscores the importance of Amazonian fungi both for understanding ecological processes and for the development of new solutions to the antimicrobial resistance challenge. This work seeks to fill current gaps in the academic literature and to contribute to future strategies for the conservation and sustainable use of regional mycobiota.

Macrofungal diversity is essential to forest ecosystems, supporting carbon cycling and plant community structure. However, anthropogenic disturbance threatens this diversity, particularly near urban areas. In Manaus, irregular settlements affect forest fragments such as the Adolpho Ducke Forest Reserve. This study described patterns of macrofungal diversity in preserved and anthropized sectors of an Amazonian forest. The study was conducted during a single field campaign in July 2024 and compared two sectors of the Adolpho Ducke Forest Reserve: one preserved forest sector and one anthropized sector. In each sector, 600 m2 were surveyed across six 10 × 10 m plots. Sampling was performed through active searches along predefined transects, using standardized field effort per plot and the same field observer/team in both sectors. Fungal diversity was analyzed using species accumulation data, morphological and molecular identification, including phylogenetic tree construction and quantification of basidiomata per taxon, and ecological indices (Shannon-Wiener diversity index, Pielou’s evenness, and Sørensen similarity index). A total of 91 basidiomata and 31 taxa were recorded in the preserved sector, with Marasmius spp., Mycena spp., Amauroderma spp., Auricularia spp., and Schizophyllum spp. as the most frequent taxa. In the anthropized sector, 15 basidiomata and 8 taxa were recorded, with Trametes sp., Marasmius puttemasii, Schizophyllum sp., Pycnoporus sp., and an unidentified Agaricales morphotype as the most frequent taxa. Ecological index analysis indicated higher diversity in the preserved sector (H′ = 3.24) and slightly lower Pielou’s evenness (J) = 0.94, whereas the anthropized sector showed lower diversity (H′ = 1.97) and slightly higher Pielou’s evenness (J) = 0.95. These results suggest that anthropogenic influence may be associated with reduced macrofungal diversity at the forest-city interface.

As infecções fúngicas representam um problema crescente de saúde pública global, especialmente em razão do número limitado de classes de antifúngicos disponíveis, do surgimento de cepas multirresistentes e da elevada toxicidade associada às terapias atuais. Nesse cenário, as naftoquinonas têm despertado grande interesse como compostos bioativos promissores, apresentando ampla diversidade de atividades farmacológicas. Esta revisão apresenta uma análise abrangente da atividade antifúngica de naftoquinonas semissintéticas frente a diferentes fungos patogênicos de relevância clínica, como Candida spp., Cryptococcus spp., Aspergillus spp. e Sporothrix spp. São discutidas a diversidade química dessas moléculas, as modificações semissintéticas e as relações estrutura–atividade, destacando a influência da posição dos substituintes e das propriedades físico-químicas na eficácia antifúngica. Além disso, são abordados os principais mecanismos de ação propostos, como o ciclo redox, a geração de espécies reativas de oxigênio, a interação com a membrana fúngica, a desregulação do equilíbrio osmótico e a ligação covalente a alvos celulares. A toxicidade e a seletividade das naftoquinonas também são analisadas com base em estudos in vitro e in vivo. De modo geral, as naftoquinonas semissintéticas se mostram estruturas químicas promissoras para o desenvolvimento de novos antifúngicos, com potencial para superar a resistência fúngica e reduzir os efeitos adversos associados às drogas convencionais.

Background/Objectives: Cryptococcosis, caused by Cryptococcus neoformans and Cryptococcus gattii species complexes, remains a significant health concern, particularly among immunocompromised patients. The emergence of antifungal resistance and toxicity of conventional treatment underscore the urgent need for novel therapeutic approaches. Combination therapies represent a promising strategy to enhance efficacy and overcome resistance. This study investigated the antifungal activity of five naphthoquinones against nine isolates of Cryptococcus spp. and assessed their synergistic effects with amphotericin B (AmB). Methods: In this study, five selected naphthoquinones were evaluated for their antifungal activity against Cryptococcus spp. isolates using broth microdilution assays to determine minimum inhibitory concentrations (MICs), according to CLSI guidelines. The potential synergistic effect with AmB was assessed using checkerboard assays, with synergy interpreted based on the fractional inhibitory concentration index (FICI). Cytotoxicity was evaluated in MRC-5 human lung fibroblast cells using the MTT assay. Results: Among the compounds tested, 2-methoxynaphthalene-1,4-dione (2-MNQ) demonstrated antifungal activity, with MIC values ranging from 3.12 to 12.5 µg/mL. Checkerboard assays revealed a synergistic interaction between 2-MNQ and AmB, with a fractional inhibitory concentration index (FICI) of 0.27. The combination reduced the MIC of AmB by 4.17-fold. These findings highlight the potential of synthetic naphthoquinones, particularly 2-MNQ, as effective antifungal agents with synergistic properties when combined with AmB. The observed synergy suggests complementary mechanisms, including increased fungal membrane permeability and oxidative stress induction. Conclusions: This study highlights the potential of 2-MNQ and 2,3-DBNQ as antifungal candidates against Cryptococcus spp., with emphasis on the synergistic interaction observed between 2-MNQ and amphotericin B. The findings reinforce the importance of structural modifications in naphthoquinones to enhance antifungal activity and support the need for further preclinical studies investigating combination therapies aimed at improving treatment efficacy in patients with cryptococcosis.

This case report documents the diagnosis and successful treatment of cryptococcosis caused by Cryptococcus gattii VGII in a 20‐month‐old male domestic shorthair cat from Manaus, Brazil, which was concurrently infected with feline immunodeficiency virus (FIV) and diagnosed with demodicosis. The cat presented with mucopurulent nasal discharge, cutaneous lesions on the neck, and a subcutaneous mass between the shoulder blades. Laboratory investigations, including fine‐needle aspiration cytology, fungal culture, and PCR‐RFLP genotyping, confirmed the presence of C. gattii VGII. The cat was treated with fluconazole (10 mg/kg/day) and topical fluralaner–moxidectin, resulting in complete clinical resolution of all lesions and associated symptoms. This report underscores the significance of considering cryptococcosis as a differential diagnosis in immunocompromised cats presenting with cutaneous or respiratory symptoms. Additionally, it highlights the importance of recognizing the Amazon region as an area of environmental prevalence of C. gattii VGII, reinforcing the need for awareness regarding its impact on animal health.

The reference methodology for evaluating antifungal susceptibility is based on determining the minimum inhibitory concentration (MIC), which is the lowest drug concentration capable of inhibiting fungal growth. However, such MIC data are insufficient to measure antifungal susceptibility if a strain is heteroresistant to the tested drug. In such cases, a minority subpopulation of fungal cells, originating from an initially susceptible lineage, can grow at antifungal drug concentrations above the MIC. In studies on fluconazole heteroresistance in Cryptococcus spp., chromosomal disomy has been shown to result in the overexpression of two genes located on chromosome 1 (Chr1) linked to antifungal resistance: ERG11 and AFR1. This review addresses the underlying mechanisms of antifungal resistance, the evolution of methods for determining antifungal susceptibility, and the clinical implications of Cryptococcus heteroresistance to fluconazole. The analysis of the findings indicated a correlation between heteroresistance and adverse clinical outcomes, although this observation still lacks definite confirmation in the literature. This highlights the need to implement more efficient therapeutic strategies and improve antifungal susceptibility and heteroresistance testing.

This study investigates the impact of moisture and wheat bran supplementation on the biological efficiency (BE) and nutritional profile of Pleurotus ostreatus (Jacq.) P. Kumm cultivated on peels of Astrocaryum aculeatum G. Mey. Utilizing a factorial design, variations in substrate composition were systematically analyzed to determine optimal conditions for mushroom yield. The methodology encompassed strain acquisition, spawn and substrate preparation, fruiting induction, biological efficiency calculation, and chemical composition analysis of both substrate and mushrooms. Results highlighted a significant variance in BE across different levels of moisture and bran supplementation, with the highest BE (45.6%) observed at 50% moisture and 5% bran supplementation. Statistical analysis revealed that both factors, individually and interactively, significantly influence BE. The chemical analysis of mushrooms showcased a nutritious profile, emphasizing the potential of this cultivation approach for producing high-value food sources. The findings contribute to the understanding of substrate optimization for mushroom cultivation, and provides information on sustainable agricultural practices and food security.