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Mycopathologia Jun 2024Aspergillosis encompasses a wide range of clinical conditions based on the interaction between Aspergillus and the host. It ranges from colonization to invasive... (Review)
Review
Aspergillosis encompasses a wide range of clinical conditions based on the interaction between Aspergillus and the host. It ranges from colonization to invasive aspergillosis. The human lung provides an entry door for Aspergillus. Aspergillus has virulence characteristics such as conidia, rapid growth at body temperature, and the production of specific proteins, carbohydrates, and secondary metabolites that allow A. fumigatus to infiltrate the lung's alveoli and cause invasive aspergillosis. Alveolar epithelial cells play an important role in both fungus clearance and immune cell recruitment via cytokine release. Although the innate immune system quickly clears conidia in immunocompetent hosts, A. fumigatus has evolved multiple virulence factors in order to escape immune response such as ROS detoxifying enzymes, the rodlet layer, DHN-melanin and toxins. Bacterial co-infections or interactions can alter the immune response, impact Aspergillus growth and virulence, enhance biofilm formation, confound diagnosis, and reduce treatment efficacy. The gut microbiome's makeup influences pulmonary immune responses generated by A. fumigatus infection and vice versa. The real-time PCR for Aspergillus DNA detection might be a particularly useful tool to diagnose pulmonary aspergillosis. Metagenomics analyses allow quick and easy detection and identification of a great variety of fungi in different clinical samples, although optimization is still required particularly for the use of NGS techniques. This review will analyze the current state of aspergillosis in light of recent discoveries in the microbiota and mycobiota.
Topics: Humans; Aspergillosis; Mycobiome; Aspergillus fumigatus; Aspergillus; Virulence Factors; Microbiota; Virulence; Metagenomics; Host-Pathogen Interactions
PubMed: 38864956
DOI: 10.1007/s11046-024-00853-2 -
Mycopathologia Jun 2024Aspergillus fumigatus is a saprophytic fungal pathogen that causes opportunistic infections in animals and humans. Azole resistance has been reported globally in human...
Aspergillus fumigatus is a saprophytic fungal pathogen that causes opportunistic infections in animals and humans. Azole resistance has been reported globally in human A. fumigatus isolates, but the prevalence of resistance in isolates from animals is largely unknown. A retrospective resistance surveillance study was performed using a collection of clinical A. fumigatus isolates from various animal species collected between 2015 and 2020. Agar-based azole resistance screening of all isolates was followed by in vitro antifungal susceptibility testing and cyp51A gene sequencing of the azole-resistant isolates. Over the 5 year period 16 (11.3%) of 142 A. fumigatus culture-positive animals harbored an azole-resistant isolate. Resistant isolates were found in birds (15%; 2/13), cats (21%; 6/28), dogs (8%; 6/75) and free-ranging harbor porpoise (33%; 2/6). Azole-resistance was cyp51A mediated in all isolates: 81.3% (T-67G/)TR/L98H, 12.5% TR/Y121F/T289A. In one azole-resistant A. fumigatus isolate a combination of C(-70)T/F46Y/C(intron7)T/C(intron66)T/M172V/E427K single-nucleotide polymorphisms in the cyp51A gene was found. Of the animals with an azole-resistant isolate and known azole exposure status 71.4% (10/14) were azole naive. Azole resistance in A. fumigatus isolates from animals in the Netherlands is present and predominantly cyp51A TR-mediated, supporting an environmental route of resistance selection. Our data supports the need to include veterinary isolates in resistance surveillance programs. Veterinarians should consider azole resistance as a reason for therapy failure when treating aspergillosis and consider resistance testing of relevant isolates.
Topics: Aspergillus fumigatus; Animals; Azoles; Drug Resistance, Fungal; Aspergillosis; Antifungal Agents; Netherlands; Microbial Sensitivity Tests; Retrospective Studies; Fungal Proteins; Birds; Cats; Dogs; Cytochrome P-450 Enzyme System
PubMed: 38864903
DOI: 10.1007/s11046-024-00850-5 -
Nature Communications Jun 2024More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. Azole antifungals represent first-line therapeutics for most...
More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. Azole antifungals represent first-line therapeutics for most of these infections but resistance is rising, therefore the identification of antifungal targets whose inhibition synergises with the azoles could improve therapeutic outcomes. Here, we generate a library of 111 genetically barcoded null mutants of Aspergillus fumigatus in genes encoding protein kinases, and show that loss of function of kinase YakA results in hypersensitivity to the azoles and reduced pathogenicity. YakA is an orthologue of Candida albicans Yak1, a TOR signalling pathway kinase involved in modulation of stress responsive transcriptional regulators. We show that YakA has been repurposed in A. fumigatus to regulate blocking of the septal pore upon exposure to stress. Loss of YakA function reduces the ability of A. fumigatus to penetrate solid media and to grow in mouse lung tissue. We also show that 1-ethoxycarbonyl-beta-carboline (1-ECBC), a compound previously shown to inhibit C. albicans Yak1, prevents stress-mediated septal spore blocking and synergises with the azoles to inhibit A. fumigatus growth.
Topics: Aspergillus fumigatus; Animals; Antifungal Agents; Protein Serine-Threonine Kinases; Fungal Proteins; Mice; Protein-Tyrosine Kinases; Dyrk Kinases; Azoles; Aspergillosis; Lung; Spores, Fungal; Female
PubMed: 38862481
DOI: 10.1038/s41467-024-48592-8 -
Angewandte Chemie (International Ed. in... Jun 2024Invasive fungal disease accounts for ~3.8 million deaths annually, an unacceptable rate that urgently prompts the discovery of new knowledge-driven treatments. We report...
Invasive fungal disease accounts for ~3.8 million deaths annually, an unacceptable rate that urgently prompts the discovery of new knowledge-driven treatments. We report the use of camelid single-domain nanobodies (Nbs) against fungal β-1,3-glucanosyltransferases (Gel) involved in β-1,3-glucan transglycosylation. Crystal structures of two Nbs with Gel4 from Aspergillus fumigatus revealed binding to a dissimilar CBM43 domain and a highly conserved catalytic domain across fungal species, respectively. Anti-Gel4 active site Nb3 showed significant antifungal efficacy in vitro and in vivo prophylactically and therapeutically against different A. fumigatus and Cryptococcus neoformans isolates, reducing the fungal burden and disease severity, thus significantly improving immunocompromised animal survival. Notably, C. deneoformans (serotype D) strains were more susceptible to Nb3 and genetic Gel deletion than C. neoformans (serotype A) strains, indicating a key role for β-1,3-glucan remodelling in C. deneoformans survival. These findings add new insights about the role of b-1,3-glucan in fungal biology and demonstrate the potential of nanobodies in targeting fungal enzymes to combat invasive fungal diseases.
PubMed: 38856634
DOI: 10.1002/anie.202405823 -
Environmental Pollution (Barking, Essex... Jun 2024The co-cultivation of fungi with microalgae facilitates microalgae harvesting and enhances heavy metal adsorption. However, the mechanisms of fungal tolerance to cadmium...
The co-cultivation of fungi with microalgae facilitates microalgae harvesting and enhances heavy metal adsorption. However, the mechanisms of fungal tolerance to cadmium (Cd) have not yet been studied in detail. In this study, functional groups of fungi were analyzed under Cd stress using Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM) to explore their morphology. Confocal laser scanning microscope (CLSM) was used to characterize the changes in the content of extracellular polysaccharides and proteins, and a decrease in the ratio of glutathione (GSH) to oxidized glutathione (GSSG) was monitored. The GSH and GSSG contents in mycelium were 7.4 and 7.9 times higher than that in the control, respectively. After 72 h of Cd treatment, the fungal extracellular polysaccharide and extracellular protein contents increased by 16 and 11.4 mg/g, respectively, compared to the control. This provided several functional groups for the complexation of Cd ions to enhance fungal Cd tolerance. The metabolomic and transcriptomic results revealed a total of 358 differential metabolites after 20, 48, and 72 h in the positive and negative ion modes, and the number of differential metabolites specific to each group was 104, 14, and 89, respectively. There were 927, 1167, and 1287 up-regulated genes, and 1301, 1480, and 1683 down-regulated genes at 20, 48, and 72 h, respectively. Energy metabolism, amino acid metabolism, and the ABC transport system are the key metabolic pathways for tolerance enhancement and heavy metal detoxification in fungi. The expression of S-cysteinosuccinic acid was significantly up-regulated after Cd stress and associated with enhanced fungal tolerance and resistance to Cd.
PubMed: 38852660
DOI: 10.1016/j.envpol.2024.124344 -
Communications Biology Jun 2024Aspergillus fumigatus represents a public health problem due to the high mortality rate in immunosuppressed patients and the emergence of antifungal-resistant isolates....
Aspergillus fumigatus represents a public health problem due to the high mortality rate in immunosuppressed patients and the emergence of antifungal-resistant isolates. Protein acetylation is a crucial post-translational modification that controls gene expression and biological processes. The strategic manipulation of enzymes involved in protein acetylation has emerged as a promising therapeutic approach for addressing fungal infections. Sirtuins, NAD-dependent lysine deacetylases, regulate protein acetylation and gene expression in eukaryotes. However, their role in the human pathogenic fungus A. fumigatus remains unclear. This study constructs six single knockout strains of A. fumigatus and a strain lacking all predicted sirtuins (SIRTKO). The mutant strains are viable under laboratory conditions, indicating that sirtuins are not essential genes. Phenotypic assays suggest sirtuins' involvement in cell wall integrity, secondary metabolite production, thermotolerance, and virulence. Deletion of sirE attenuates virulence in murine and Galleria mellonella infection models. The absence of SirE alters the acetylation status of proteins, including histones and non-histones, and triggers significant changes in the expression of genes associated with secondary metabolism, cell wall biosynthesis, and virulence factors. These findings encourage testing sirtuin inhibitors as potential therapeutic strategies to combat A. fumigatus infections or in combination therapy with available antifungals.
Topics: Aspergillus fumigatus; Sirtuins; Virulence; Animals; Mice; Aspergillosis; Acetylation; Fungal Proteins; Gene Expression Regulation, Fungal; Virulence Factors; Moths
PubMed: 38851817
DOI: 10.1038/s42003-024-06383-3 -
Macromolecular Bioscience Jun 2024The ubiquitous mold Aspergillus fumigatus (A. fumigatus) is one of the main fungal pathogens causing invasive infections in immunocompromised humans. Conventional...
The ubiquitous mold Aspergillus fumigatus (A. fumigatus) is one of the main fungal pathogens causing invasive infections in immunocompromised humans. Conventional antifungal agents exhibit limited efficacy and often cause severe side effects. Nanoparticle-based antifungal delivery provides a promising alternative, which can increase local drug concentration while mitigating toxicity, thereby enhancing treatment efficacy. Previous research underscores the potential of poly(glycidol)-based nanogels (NG) with negative surface charge as carriers for delivering antifungals to A. fumigatus hyphae. In this study, we tailored NG with 2-carboxyethyl acrylate (CEA) or with phosphoric acid 2-hydroxyethyl acrylate (PHA). We discovered that quenching with PHA clearly improved the adhesion of NG to hyphal surface and the internalization of NG into the hyphae under protein-rich conditions, surpassing the outcomes of non-quenched and CEA-quenched NG. This enhancement cannot be solely attributed to an increase in negative surface charge but appears to be contingent on the functional group of the quencher. Furthermore, we demonstrate that itraconazole-loaded, PHA-functionalized nanogels (NGxPHA-ITZ) showed lower MIC in vitro and superior therapeutic effect in vivo against A. fumigatus compared to pure itraconazole. This confirms NGxPHA as a promising antifungal delivery system. This article is protected by copyright. All rights reserved.
PubMed: 38850104
DOI: 10.1002/mabi.202400082 -
Frontiers in Cellular and Infection... 2024Lower respiratory tract infections represent prevalent ailments. Nonetheless, current comprehension of the microbial ecosystems within the lower respiratory tract...
BACKGROUND
Lower respiratory tract infections represent prevalent ailments. Nonetheless, current comprehension of the microbial ecosystems within the lower respiratory tract remains incomplete and necessitates further comprehensive assessment. Leveraging the advancements in metagenomic next-generation sequencing (mNGS) technology alongside the emergence of machine learning, it is now viable to compare the attributes of lower respiratory tract microbial communities among patients across diverse age groups, diseases, and infection types.
METHOD
We collected bronchoalveolar lavage fluid samples from 138 patients diagnosed with lower respiratory tract infections and conducted mNGS to characterize the lung microbiota. Employing various machine learning algorithms, we investigated the correlation of key bacteria in patients with concurrent bronchiectasis and developed a predictive model for hospitalization duration based on these identified key bacteria.
RESULT
We observed variations in microbial communities across different age groups, diseases, and infection types. In the elderly group, exhibited the highest relative abundance, followed by and . and emerged as the dominant genera at the genus level in the younger group, while and were prevalent species. Within the bronchiectasis group, dominant bacteria included , , and . Significant differences in the presence of were noted between the bronchiectasis group and the control group. In the group with concomitant fungal infections, the most abundant genera were and , with and as the predominant species. Notable differences were observed in the presence of , , , , and between the group with concomitant fungal infections and the bacterial group. Machine learning algorithms were utilized to select bacteria and clinical indicators associated with hospitalization duration, confirming the excellent performance of bacteria in predicting hospitalization time.
CONCLUSION
Our study provided a comprehensive description of the microbial characteristics among patients with lower respiratory tract infections, offering insights from various perspectives. Additionally, we investigated the advanced predictive capability of microbial community features in determining the hospitalization duration of these patients.
Topics: Humans; Machine Learning; Metagenomics; Middle Aged; Respiratory Tract Infections; Aged; Male; Female; Adult; Bacteria; Bronchoalveolar Lavage Fluid; Microbiota; High-Throughput Nucleotide Sequencing; Young Adult; Bronchiectasis; Aged, 80 and over; Metagenome; Adolescent; Lung; Hospitalization
PubMed: 38846353
DOI: 10.3389/fcimb.2024.1385562 -
IScience Jun 2024Hundreds of spores of are inhaled daily by human beings, representing a constant, possibly fatal, threat to respiratory health. The small size of spores suggests that...
Hundreds of spores of are inhaled daily by human beings, representing a constant, possibly fatal, threat to respiratory health. The small size of spores suggests that interactions with alveolar epithelial cells (AECs) are frequent; thus, we hypothesized that spore uptake by AECs is important for driving fungal killing and susceptibility to -related disease. Using single-cell approaches to measure spore uptake and its outcomes , we demonstrate that spores are internalized and killed by AECs during whole-animal infection. Moreover, comparative analysis of primary human AECs from healthy and chronic obstructive pulmonary disease (COPD) donors revealed significant alterations in the uptake and killing of spores in COPD-derived AECs. We conclude that AECs contribute to the killing of spores and that dysregulation of curative AEC responses in COPD may represent a driver of -related diseases.
PubMed: 38846001
DOI: 10.1016/j.isci.2024.109939 -
Applied and Environmental Microbiology Jun 2024Airborne triazole-resistant spores of the human fungal pathogen are a significant human health problem as the agricultural use of triazoles has been selecting for...
Airborne triazole-resistant spores of the human fungal pathogen are a significant human health problem as the agricultural use of triazoles has been selecting for cross-resistance to life-saving clinical triazoles. However, how to quantify exposure to airborne triazole-resistant spores remains unclear. Here, we describe a method for cost-effective wide-scale outdoor air sampling to measure both spore abundance as well as antifungal resistance fractions. We show that prolonged outdoor exposure of sticky seals placed in delta traps, when combined with a two-layered cultivation approach, can regionally yield sufficient colony-forming units (CFUs) for the quantitative assessment of aerial resistance levels at a spatial scale that was up to now unfeasible. When testing our method in a European pilot sampling 12 regions, we demonstrate that there are significant regional differences in airborne CFU numbers, and the triazole-resistant fraction of airborne spores is widespread and varies between 0 and 0.1 for itraconazole (∼4 mg/L) and voriconazole (∼2 mg/L). Our efficient and accessible air sampling protocol opens up extensive options for fine-scale spatial sampling and surveillance studies of airborne IMPORTANCE is an opportunistic fungal pathogen that humans and other animals are primarily exposed to through inhalation. Due to the limited availability of antifungals, resistance to the first choice class of antifungals, the triazoles, in can make infections by this fungus untreatable and uncurable. Here, we describe and validate a method that allows for the quantification of airborne resistance fractions and quick genotyping of TR-types. Our pilot study provides proof of concept of the suitability of the method for use by citizen-scientists for large-scale spatial air sampling. Spatial air sampling can open up extensive options for surveillance, health-risk assessment, and the study of landscape-level ecology of , as well as investigating the environmental drivers of triazole resistance.
PubMed: 38842339
DOI: 10.1128/aem.00271-24