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Microbiology Spectrum Dec 2021In Aspergillus fumigatus, the repetitive region of the gene is one of the most frequently used loci for intraspecies typing of this human pathogenic mold. Using PCR...
In Aspergillus fumigatus, the repetitive region of the gene is one of the most frequently used loci for intraspecies typing of this human pathogenic mold. Using PCR amplification and Sanger sequencing of only a single marker, typing is readily available to most laboratories and highly reproducible. Here, I evaluate the usefulness of the marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. After resolving nomenclature conflicts from published studies and adding novel types, the number of known types now adds up to 38. Their distribution mostly correlates with A. fumigatus population structure, and they are also meaningful for narrowly defined cases of azole resistance phenotypes. Isolates carrying the pandemic resistance allele TR/L98H show signs of interclade crossing of strains with t02 or t04A, into the t11 clade. Furthermore, absolute differences in voriconazole MIC values between t02/t04B versus t11 TR/L98H isolates indicate that the genetic background of resistance mutations may have a pivotal role in cross-resistance phenotypes and, thus, clinical outcome and environmental selection. Despite the general genetic similarity of isolates with identical types, outcrossing into other clades is also observed. The type alone, therefore, does not sufficiently discriminate genetic clades to be used as the sole marker in epidemiologic studies. Aspergillus fumigatus is a ubiquitously distributed saprophytic mold and a leading cause of invasive aspergillosis in human hosts. Pandemic azole-resistant strains have emerged on a global scale, which are thought to be propagated through use of azole-based fungicides in agriculture. To perform epidemiologic studies, genetic typing of large cohorts is key. Here, I evaluate the usefulness of the frequently used marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. The phylogenetic distribution of types mostly correlates with A. fumigatus population structure and is also meaningful for narrowly defined cases of azole resistance phenotypes. Nevertheless, outcrossing of into other clades is also observed. The type alone, therefore, does not sufficiently discriminate genetic clades and should not be used as the sole marker in epidemiologic studies.
Topics: Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Drug Resistance, Fungal; Fungal Proteins; Genetic Markers; Humans; Membrane Proteins; Microbial Sensitivity Tests; Molecular Typing; Mycological Typing Techniques; Polymorphism, Single Nucleotide; Voriconazole
PubMed: 34787484
DOI: 10.1128/Spectrum.01214-21 -
Research in Veterinary Science Nov 2023Antifungal-resistant fungi, including Aspergillus fumigatus and other Aspergillus species, pose an urgent threat to human and animal health. Furthermore, the...
Antifungal-resistant fungi, including Aspergillus fumigatus and other Aspergillus species, pose an urgent threat to human and animal health. Furthermore, the environmental route of azole resistance selection due to the widespread use of azole fungicides in crop protection and other applications is a major public health issue. Although environmental surveillance of fungi is frequently performed in many zoological parks and wildlife rehabilitation centers, the antifungal susceptibility of recovered isolates is only rarely analyzed, which precludes a clear assessment of the threat posed by these fungi to captive animals. In this study, we assessed the presence of airborne azole-resistant Aspergillus spp., including the so-called 'cryptic species' (i.e., species which are phenotypically similar to more well-known aspergilli but clearly constitute different phylogenetic lineages) in a zoological park located in the city of Madrid, Spain. In general, our results revealed a low prevalence A. fumigatus and cryptic aspergilli with decreased susceptibility to azoles. However, we detected an A. fumigatus isolate with the TR/L98H mutation in the gene encoding the lanosterol 14α-demethylase (Cyp51A), consisting of a tandem repeat of 34 base pairs in the promoter region and a lysine to histidine substitution at codon 98. Notably, this TR/L98H mutation has been linked to the environmental route of azole resistance selection, thus highlighting the 'One Health' dimension of the emerging problem of antifungal resistance. In this context, continuous environmental surveillance of azole-resistant aspergilli in zoological parks and other similar animal facilities is recommended.
Topics: Animals; Humans; Aspergillus fumigatus; Azoles; Antifungal Agents; Phylogeny; Fungal Proteins; Aspergillus; Fungi; Mutation; Microbial Sensitivity Tests
PubMed: 37657393
DOI: 10.1016/j.rvsc.2023.104993 -
Journal of Proteome Research May 2020Fungal spores and hyphal fragments play an important role as allergens in respiratory diseases. In this study, we performed trypsin shaving and secretome analyses to...
Fungal spores and hyphal fragments play an important role as allergens in respiratory diseases. In this study, we performed trypsin shaving and secretome analyses to identify the surface-exposed proteins and secreted/shed proteins of conidia, respectively. We investigated the surface proteome under different conditions, including temperature variation and germination. We found that the surface proteome of resting conidia is not static but instead unexpectedly dynamic, as evidenced by drastically different surface proteomes under different growth conditions. Knockouts of two abundant surface proteins, ScwA and CweA, were found to function only in fine-tuning the cell wall stress response, implying that the conidial surface is very robust against perturbations. We then compared the surface proteome of to other allergy-inducing molds, including , , and , and performed comparative proteomics on resting and swollen conidia, as well as secreted proteins from germinating conidia. We detected 125 protein ortholog groups, including 80 with putative catalytic activity, in the extracellular region of all four molds, and 42 nonorthologous proteins produced solely by . Ultimately, this study highlights the dynamic nature of the conidial surface and provides targets for future diagnostics and immunotherapy.
Topics: Allergens; Aspergillus fumigatus; Fungal Proteins; Hypersensitivity; Hyphae; Membrane Proteins; Proteome; Spores, Fungal
PubMed: 32233371
DOI: 10.1021/acs.jproteome.0c00013 -
MSphere Aug 2019The genetic stability of every living organism depends on accurate DNA replication and repair systems. Here, we investigated the mismatch repair (MMR) gene MshA and how...
The genetic stability of every living organism depends on accurate DNA replication and repair systems. Here, we investigated the mismatch repair (MMR) gene MshA and how it impacts virulence and the evolution of azole resistance. We examined gene variation in 62 environmental and clinical strains. We have observed 12 strains with variants (18.2%), and 8 strains among them showed missense variants. We demonstrated that null mutants are haploid and have conserved karyotypes with discrete gross chromosomal rearrangements. The Δ strains are not sensitive to several DNA-damaging agents. The lack of caused a significant reduction of virulence of in a neutropenic murine model of invasive pulmonary aspergillosis and in the invertebrate alternative model Wild-type and Δ populations did not show any significant changes in drug resistance acquisition after they were transferred 10 times in minimal medium in the absence of any stress. However, these populations rapidly acquired virulence in the Δ background and high levels of resistance to posaconazole in the presence of this drug (at least 200-fold-higher levels of resistance than those derived from the wild-type strain). Taken together, these results suggest that genetic instability caused by Δ mutations can confer an adaptive advantage, mainly increasing posaconazole resistance and virulence acquisition. Invasive aspergillosis (IA) has emerged as one of the most common life-threatening fungal diseases in immunocompromised patients, with mortality rates as high as 90%. Systemic fungal infections such as IA are usually treated with triazoles; however, epidemiological research has shown that the prevalence of azole-resistant isolates has increased significantly over the last decade. There is very little information about the importance of genomic stability for population structure, azole resistance, and virulence. Here, we decided to investigate whether the mismatch repair system could influence azole resistance and virulence, focusing on one of the components of this system, Although the mutation frequency of (the homologue) is low in environmental and clinical isolates, our results indicate that loss of function can provide increased azole resistance and virulence when selected for. These results demonstrate the importance of genetic instability in as a possible mechanism of evolving azole resistance and establishing fitness in the host.
Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Azoles; DNA Mismatch Repair; Drug Resistance, Fungal; Female; Fungal Proteins; Larva; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Moths; MutS Homolog 2 Protein; Neutropenia; Sequence Homology; Virulence
PubMed: 31391280
DOI: 10.1128/mSphere.00416-19 -
MBio Oct 2022The human opportunistic pathogen Aspergillus fumigatus is recognized for its versatile cell wall when it comes to remodeling its components in adaptation to external...
The human opportunistic pathogen Aspergillus fumigatus is recognized for its versatile cell wall when it comes to remodeling its components in adaptation to external threats, and this remodeling renders it refractory to antifungals targeting cell wall biosynthesis. A specific role for general sugar metabolism in the regulation of the synthesis of cell wall polymers has been previously demonstrated. Delving deeper into central sugar metabolism may reveal unexpected fundamental aspects in cell wall construction, as shown by the work of Zhou and coworkers (Y. Zhou, K. Yan, Q. Qin, O.G. Raimi, et al., mBio 13:e01426-22, 2022, https://doi.org/10.1128/mbio.01426-22) on the roles of the phosphoglucose isomerase of A. fumigatus in cell wall biosynthesis.
Topics: Antifungal Agents; Aspergillus fumigatus; Cell Wall; Fungal Proteins; Glucose-6-Phosphate Isomerase; Polymers; Sugars; Virulence
PubMed: 36094091
DOI: 10.1128/mbio.02104-22 -
Mycoses Nov 2021Mutations in cyp51A gene are known as main mechanisms of azole resistance in Aspergillus fumigatus, whereas azole-susceptible strains also carry cyp51A mutations... (Comparative Study)
Comparative Study
BACKGROUND
Mutations in cyp51A gene are known as main mechanisms of azole resistance in Aspergillus fumigatus, whereas azole-susceptible strains also carry cyp51A mutations (polymorphisms). The polymorphisms found in Europe mainly consist of two combinations of mutations, that is combinations of five single-nucleotide polymorphisms (SNPs) of cyp51A, referred to as cyp51A-5SNPs, and combinations of three SNPs of cyp51A, referred to as cyp51A-3SNPs. Few studies have compared the distributions of cyp51A polymorphisms between different regions.
OBJECTIVES
The aim of this study was to investigate the regional differences of cyp51A polymorphisms.
METHODS
We compared the proportions of cyp51A polymorphisms in clinical and environmental strains isolated in various countries, and analysed the strains phylogenetically using short tandem repeats (STRs) and whole-genome sequence (WGS).
RESULTS
Among the Japanese strains, 15 out of 98 (15.3%) clinical strains and 8 out of 95 (8.4%) environmental strains had cyp51A polymorphisms. A mutation of cyp51A was the most prevalent polymorphism in both clinical (n = 14, 14.3%) and environmental strains (n = 3, 3.2%). Only one environmental strain harboured cyp51A-5SNPs, which was reported to be the most prevalent in Europe. For phylogenetic analyses using STRs and WGS, 183 and 134 strains, respectively, were employed. They showed that most of the strains with cyp51A clustered in the clades different from those of the strains with cyp51A-5SNPs and cyp51A-3SNPs as well as from those with TR /L98H mutations.
CONCLUSIONS
This study suggests that there are genetic differences between cyp51A polymorphisms of A. fumigatus in Japan and Europe.
Topics: Animals; Antifungal Agents; Aspergillus fumigatus; Bombyx; Chronic Disease; Cytochrome P-450 Enzyme System; Environmental Microbiology; Europe; Fungal Proteins; Genotype; Humans; Invasive Pulmonary Aspergillosis; Japan; Microbial Sensitivity Tests; Mutation; Phylogeny; Polymorphism, Single Nucleotide; Pulmonary Aspergillosis; Virulence; Whole Genome Sequencing
PubMed: 34558115
DOI: 10.1111/myc.13370 -
Applied and Environmental Microbiology Oct 2021An efficient reactive oxygen species (ROS) detoxification system is vital for the survival of the pathogenic fungus Aspergillus fumigatus within the host high-ROS...
An efficient reactive oxygen species (ROS) detoxification system is vital for the survival of the pathogenic fungus Aspergillus fumigatus within the host high-ROS environment of the host. Therefore, identifying and targeting factors essential for oxidative stress response is one approach to developing novel treatments for fungal infections. The oxidation resistance 1 (Oxr1) protein is essential for protection against oxidative stress in mammals, but its functions in pathogenic fungi remain unknown. The present study aimed to characterize the role of an Oxr1 homolog in A. fumigatus. The results indicated that the OxrA protein plays an important role in oxidative stress resistance by regulating the catalase function in A. fumigatus, and overexpression of catalase can rescue the phenotype associated with OxrA deficiency. Importantly, the deficiency of decreased the virulence of A. fumigatus and altered the host immune response. Using the Aspergillus-induced lung infection model, we demonstrated that the mutant strain induced less tissue damage along with decreased levels of lactate dehydrogenase (LDH) and albumin release. Additionally, the mutant caused inflammation at a lower degree, along with a markedly reduced influx of neutrophils to the lungs and a decreased secretion of cytokine usually associated with recruitment of neutrophils in mice. These results characterize the role of OxrA in A. fumigatus as a core regulator of oxidative stress resistance and fungal pathogenesis. Knowledge of ROS detoxification in fungal pathogens is useful in the design of new antifungal drugs and could aid in the study of oxidative stress resistance mechanisms. In this study, we demonstrate that OxrA protein localizes to the mitochondria and functions to protect against oxidative damage. We demonstrate that OxrA contributes to oxidative stress resistance by regulating catalase function, and overexpression of catalase (CatA or CatB) can rescue the phenotype that is associated with OxrA deficiency. Remarkably, a loss of OxrA attenuated the fungal virulence in a mouse model of invasive pulmonary aspergillosis and altered the host immune response. Therefore, our finding indicates that inhibition of OxrA might be an effective approach for alleviating A. fumigatus infection. The present study is, to the best of our knowledge, a pioneer in reporting the vital role of Oxr1 protein in pathogenic fungi.
Topics: Animals; Aspergillosis; Aspergillus fumigatus; Catalase; Fungal Proteins; Mice; Oxidative Stress; Reactive Oxygen Species; Virulence
PubMed: 34524893
DOI: 10.1128/AEM.01120-21 -
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 -
NPJ Biofilms and Microbiomes Oct 2022The filamentous fungus Aspergillus fumigatus is an ubiquitous mold that can cause invasive pulmonary infections in immunocompromised patients. Within the lung, A.... (Review)
Review
Filamentous fungal biofilms: Conserved and unique aspects of extracellular matrix composition, mechanisms of drug resistance and regulatory networks in Aspergillus fumigatus.
The filamentous fungus Aspergillus fumigatus is an ubiquitous mold that can cause invasive pulmonary infections in immunocompromised patients. Within the lung, A. fumigatus forms biofilms that can enhance resistance to antifungals and immune defenses, highlighting the importance of defining the mechanisms underlying biofilm development and associated emergent properties. A. fumigatus biofilms display a morphology and architecture that is distinct from bacterial and yeast biofilms. Moreover, A. fumigatus biofilms display unique characteristics in the composition of their extracellular matrix (ECM) and the regulatory networks governing biofilm formation. This review will discuss our current understanding of the form and function of A. fumigatus biofilms, including the unique components of ECM matrix, potential drug resistance mechanisms, the regulatory networks governing A. fumigatus biofilm formation, and potential therapeutics targeting these structures.
Topics: Humans; Aspergillus fumigatus; Antifungal Agents; Biofilms; Fungi; Extracellular Matrix; Drug Resistance
PubMed: 36261442
DOI: 10.1038/s41522-022-00347-3 -
Mycoses Apr 2021Patients with chronic lung diseases, including cystic fibrosis (CF), are frequently sensitized to Aspergillus fumigatus. Whether patients with non-CF bronchiectasis...
BACKGROUND
Patients with chronic lung diseases, including cystic fibrosis (CF), are frequently sensitized to Aspergillus fumigatus. Whether patients with non-CF bronchiectasis develop sensitization to A fumigatus remains unknown.
OBJECTIVE
To evaluate the prevalence of sensitization and chronic infection with A fumigatus in subjects with bronchiectasis. We also performed a multivariate logistic regression analysis to identify factors predicting sensitization and chronic A fumigatus infection.
METHODS
Subjects with bronchiectasis were investigated with serum A fumigatus-specific IgE and IgG, and sputum cultures for bacteria, fungus and mycobacteria. We defined A fumigatus sensitization and chronic A fumigatus infection as serum A fumigatus-specific IgE and IgG > 0.35 kUA/L and >27 mgA/L, respectively. We excluded subjects with bronchiectasis secondary to allergic bronchopulmonary aspergillosis.
RESULTS
We included 258 subjects (TB [n = 155], idiopathic [n = 66] and other causes [n = 37]) with bronchiectasis. The prevalence of Aspergillus sensitization, chronic Aspergillus infection, and both sensitization and chronic infection was 29.5% (76/258), 76% (196/258) and 26% (68/258), respectively. In a multivariate logistic regression analysis, TB-related bronchiectasis was an independent risk factor for Aspergillus sensitization. Chronic Aspergillus infection was predicted by the duration of symptoms and specific aetiologies (tuberculosis and idiopathic) of bronchiectasis. The growth of Aspergillus species was also frequent in the TB group compared with other causes (32% vs 2%; P < .001).
CONCLUSIONS
We found a significant occurrence of Aspergillus sensitization and chronic infection in non-CF bronchiectasis, especially in TB bronchiectasis. In addition to Aspergillus sensitization, investigations for chronic Aspergillus infection should be routinely performed in non-CF bronchiectasis, both at diagnosis and during follow-up.
Topics: Adult; Aspergillosis; Aspergillosis, Allergic Bronchopulmonary; Aspergillus fumigatus; Bronchiectasis; Cystic Fibrosis; Female; Humans; Immunoglobulin E; Immunoglobulin G; India; Logistic Models; Male; Middle Aged; Prevalence; Prospective Studies; Sputum
PubMed: 33332671
DOI: 10.1111/myc.13229