Taxonomy of Allergenic Fungi

Assessing population exposure to airborne fungi in the UK over one year using high-throughput sequencing (HTS) metabarcoding methods

Airborne fungi are significant contributors to allergic and infectious disease. While microscopy remains the primary method for fungal identification, high-throughput sequencing (HTS) enables untargeted analysis of a much wider range of environmental taxa. This study used HTS to better characterise airborne fungal composition over a 12-month period in two UK locations, the city of Leicester in central England and a rural site in Chilton (Oxfordshire) approximately 115 km further south. Air samples were collected over a year. A subset of 240 samples (120 per location) were analysed by HTS with a combined internal transcribed spacer region (ITS2) and D1/D2 region of the large subunit (LSU) metabarcoding approach. With statistical imputation a representative 12-month dataset was created. Differences in fungal diversity and composition were explored, incorporating meteorological data. HTS analysis identified 272 fungal genera across locations and seasons, approximately 4-fold more than in other studies using traditional microscopy methods. Fungal diversity, richness and composition at the two locations were broadly similar with some taxa-specific differences likely reflecting land-use types (urban vs rural) and/or local meteorological variables. In particular, air temperature and precipitation significantly influenced fungal composition. This study demonstrates the value of HTS for characterising airborne fungi. While it does not provide absolute quantitation, HTS could be used as a screening tool to identify novel associations between fungal exposure and health outcomes, and should be used in combination with quantitative methods, such as microscopy and quantitative PCR (qPCR). Greater spatial and temporal understanding of the wide range of airborne fungal exposure is crucial for exploring associated health impacts and developing improved public health interventions and alert systems for susceptible individuals.

Microbial exposure and diversity in Norwegian shrimp processing plants

Seafood processing workers have a high prevalence of respiratory symptoms and occupational asthma, primarily attributed to allergenic protein exposure. However, exposure to airborne microorganisms from raw materials can also contribute to allergic sensitization and other respiratory ailments. This study aimed to assess microbial exposure in shrimp processing plants and identify susceptible work tasks. Full-shift personal air samples were collected from two Norwegian shrimp processing plants across five distinct work processes: thawing, truck driving, cooking-peeling (technician), packing, and flour production. The samples were analyzed for the presence of endotoxin, Toll-Like Receptor (TLR) activation, bacterial and fungal DNA copies, and microbial composition. Endotoxin levels were generally low, with only one sample (98 EU/m3) exceeding the recommended occupational exposure limit (OEL). A significant TLR2 activation was observed among thawers, indicating the presence of microbial ligands capable of triggering an immune response. The median bacterial (75 × 103 DNA copies/m3) and fungal (3,301 × 103 DNA copies/m3) exposure were highest among the flour production workers, while the lowest bacterial and fungal exposure was among packers (1.5 × 103 DNA copies/m3) and technicians (337 DNA copies/m3), respectively. Several bacterial and fungal species were identified, including ten allergenic and sixteen pathogenic species. Sporobolomyces roseus and Saccharomyces cerevisiae were the two most frequently identified allergenic fungal species. Among the pathogenic bacterial species, Prevotella nigrescens and Roseomonas gilardii were the two most detected species. While the pathogenic species were identified mainly in the packing, truck driving, and flour production work processes, most of the allergenic species were found in all work processes. Altogether, work processes before the cooking of shrimp (thawing and truck driving) had higher endotoxin, bacterial load, and species richness than after cooking, suggesting that these work tasks are susceptible to bacterial exposure and that the cooking process significantly reduces bacterial exposure. By shedding light on microbial exposure and identifying high-exposure work tasks, this study enables the development of targeted interventions and implementation of measures for the prevention of occupational diseases.

Biological and biochemical studies on cell surface functions in microorganisms used in brewing and fermentation industry

When brewing microorganisms, which include bacteria and fungi, act on solid cereal substrates, the microbial cell surface interacts with the substrate. When microorganisms use sugars and amino acids released by hydrolysis of the substrate, this occurs on the cell surface. Throughout my career, I have focused on functional studies of cell surface molecules such as solute transporters, cell wall components, and bio-surfactants and applied the knowledge obtained to the development of fermentation technologies. In this review, I describe (i) catabolite control by sugar transporters and energy generation coupled with amino acid decarboxylation in lactic acid bacteria; (ii) recruitment of a polyesterase by the fungal bio-surfactant proteins to polyesters and subsequent promotion of polyester hydrolysis; and (iii) hyphal aggregation via cell wall α-1,3-glucan and galactosaminogalactan in aspergilli and the development of a novel liquid culture method with hyphal dispersed mutants lacking these two polysaccharides.

Indoor and Outdoor Fungal Allergens and Impacts on Respiratory Allergic Disease

Humans have a historic and intimate relationship with fungi. Fungi cause decay in the environment and a variety of human disease states including respiratory disease. Immunocompromised persons are particularly susceptible to fungal infection; however, the greater impact of fungi in general is through allergic mechanisms. This impact has been extensively documented in epidemiologic studies. Typically, fungal spore exposure has been examined in the outdoor environment; however, in recent decades, lifestyle changes have resulted in increased concern about fungi in the indoor environment. This review examines evidence for the relationship between fungal exposure and respiratory disease as indicated by documented physician interactions comparing times of high spore exposure with times of low exposure. The taxa Alternaria has been especially associated with respiratory difficulties, but there is extensive cross-reactivity among fungal allergens. We examine recent evidence that damp housing and associated indoor fungal load relate to respiratory disease and some possible mechanisms by which fungal products might cause sensitivity. We also offer some steps allergists might suggest to their patients that may help alleviate fungal exposure.

In silico evaluation of the potential allergenicity of a fungal biomass from Rhizomucor pusillus for use as a novel food ingredient

The world's hunger for novel food ingredients drives the development of safe, sustainable, and nutritious novel food products. For foods containing novel proteins, potential allergenicity of the proteins is a key safety consideration. One such product is a fungal biomass obtained from the fermentation of Rhizomucor pusillus. The annotated whole genome sequence of this strain was subjected to sequence homology searches against the AllergenOnline database (sliding 80-amino acid windows and full sequence searches). In a stepwise manner, proteins were designated as potentially allergenic and were further compared to proteins from commonly consumed foods and from humans. From the sliding 80-mer searches, 356 proteins met the conservative >35% Codex Alimentarius threshold, 72 of which shared ≥50% identity over the full sequence. Although matches were identified between R. pusillus proteins and proteins from allergenic food sources, the matches were limited to minor allergens from these sources, and they shared a greater degree of sequence homology with those from commonly consumed foods and human proteins. Based on the in silico analysis and a literature review for the source organism, the risk of allergenic cross-reactivity of R. pusillus is low.

Bayesian analysis suggests independent development of sensitization to different fungal allergens

Background

Fungi are known for their ability to cause allergies, but data on individual sensitization to them are insufficient. The purpose of the study was to carry out a comprehensive analysis of the fungal allergens' sensitization profile in the Ukrainian population and to determine both population and individual sensitivity to these allergens.

Methods

We utilized a set of ALEX allergy test data from 20,033 inhabitants of 17 regions of Ukraine from 1 to 89 years conducted in 2020-2022. A complex of programs in the Python language was developed and Bayesian network analysis was applied to determine the sensitivity combinations in individual patients to various fungal components.

Results

Sensitivity to Alt a 1 dominated and was observed in 79.39% of patients, and 62.17% of them were sensitive solely to Alt a 1. Exclusive sensitivity to Mala s 6 was second in individual patient profiles with a frequency of 4.06%. Combined sensitivity to Alt a 1 - Asp f 3 was third with a share of 3.28%. Pen ch and Cla h extracts stimulated the production of the lowest median sIgE levels. The highest median sIgE levels were for Alt a 1, Mala s 11 and Asp f 6, respectively. Median sIgE levels increased in adults compared to children for all components of Aspergillus fumigatus, as well as for Mala s 5 and Mala s 11. In the rest of the cases, they decreased in adults compared to children. The sensitization rates to fungi in general and specifically to Alternaria were lower in the western parts of Ukraine, especially in the Carpathian region, situated within the Broad-leaved Forest zone. The results of Bayesian modeling revealed that in the case of Alt a 1, the simultaneous absence of sensitivity to Cla h 8, Mala s 11, Mala s 5 and Mala s 6 molecules could condition the presence of sensitization to the major Alternaria allergen with a probability of 92.42%. In all other cases, there was a high probability of absence of sensitivity to particular allergen against the background of absence of sensitivity to other ones, which may indicate the independent development of sensitization to different fungal allergens.

Conclusions

Sensitivity to Alt a 1 dominated in the studied population with a lower rate in the western regions. The highest median sIgE levels were induced by Alt a 1, Mala s 11 and Asp f 6. Bayesian Analysis suggest a high probability of the independent development of sensitization to different fungal allergens. The idea that sensitization to one allergen may be protective against sensitization to another one(s) requires further clinical study.

Fungal Sensitization and Human Allergic Disease

PURPOSE OF THE REVIEW

Fungal sensitizations have been associated with hypersensitivity reactions with variable levels of evidence available to link types of fungi with human disease. We conducted systematic reviews of the literature to identify the strength of evidence linking lesser-studied fungi for which there are commercially available extracts to identify populations in which they were useful in clinical practice.

RECENT FINDINGS

Excluding five fungi for which hundreds of articles were identified, there are 54 articles on the remaining fungi with clinical data. For 12 of the fungi, the prevalence of fungal sensitization varies in different hypersensitivity disorders due to factors related to geographic areas, age, and other underlying medical conditions. There were no studies linking seven genera to human disease. Most of the commercially available fungal extracts are uncommonly associated with hypersensitivity reactions in humans. Specific extracts may be useful in particular disease states such as allergic fungal sinusitis or allergic bronchopulmonary mycosis, or when routine testing fails to identify a cause of uncontrolled disease, such as in asthma.

Fungal and bacterial species richness in biodeteriorated seventeenth century Venetian manuscripts

Historical paper documents are susceptible to complex degradation processes, including biodeterioration, which can progressively compromise their aesthetic and structural integrity. This study analyses seventeenth century handwritten historical letters stored at the Correr Museum Library in Venice, Italy, exhibiting pronounced signs of biodeterioration. The techniques used encompassed traditional colony isolation on agar plates and proteomics analyses, employing nanoscale liquid chromatography coupled with high-resolution mass spectrometry (nano-LC-MS). Fluorescence microscopy was used for the first time in the historical paper biodeterioration context to supplement the conventional stereoscopic, optical, and scanning electron microscopic imaging techniques. This method enables the visualisation of microorganisms beyond and beneath the paper's surface through their natural intrinsic autofluorescence in a non-invasive and non-destructive way. The results demonstrate a diverse, complex, and abundant microbiota composed of coexisting fungal and bacterial species (Ascomycota, Mucoromycota, Basidiomycota, Proteobacteria, and Actinobacteria), along with mite carcasses, insects, parasites, and possibly protists. Furthermore, this study reveals certain species that were not previously documented in the biodeterioration of historical paper, including human pathogens, such as Histoplasma capsulatum, Brucella, Candida albicans, and species of Aspergillus (A. flavus, A. fumigatus, A. oryzae, A. terreus, A. niger) known to cause infections or produce mycotoxins, posing substantial risk to both artefacts and humans.

Assessing the contributions of phylogenetic and environmental determinants of allergic cosensitization to fungi in humans

BACKGROUND

Understanding how allergies to 1 environmental fungus can lead to cosensitization to related fungi is important for the clinical management of allergies. Cosensitization can be caused by monosensitization combined with antibody cross-reactivity, or by coexposures driving independent sensitizations. A pioneering study showed that patterns of IgE cosensitization among 17 fungal species mirror fungal phylogeny. This could reflect either epitope or habitat similarity. Thanks to an improved understanding of fungal phylogeny, larger serologic testing datasets, and environmental data on household fungi, we can now characterize the relationship between cosensitization, species similarity, and likely coexposure with greater precision.

OBJECTIVE

To assess the degree to which IgE cosensitization in a group of 17 fungi can be attributed to species similarity or environmental coexposure.

METHODS

Cosensitization patterns among 17 fungal species were estimated from a dataset of approximately 8 million serologic tests on 1.6 million patients. Linear regression of cosensitization on phylogenetic distance and imputed coexposure was performed. In addition, branch lengths for the phylogenetic tree were re-estimated on the basis of cosensitization and compared with corresponding phylogenetic branch lengths.

RESULTS

Phylogenetic distance explains much of the observed cosensitization (adjusted r2 = .68, p < .001). Imputed environmental coexposures and test co-ordering patterns do not significantly predict cosensitization. Branch length comparisons between the cosensitization and phylogenetic trees identified several species as less cosensitizing than phylogenetic distance predicts.

CONCLUSION

Combined evidence from clinical IgE testing data on fungi, along with phylogenetic and environmental exposure data, supports the hypothesis that cosensitization is caused primarily by monosensitization plus cross-reactivity, rather than multisensitization. A serologic test result should be interpreted as pointing to a group of related species that include the sensitizing agent rather than as uniquely identifying the agent. The identified patterns of cross-reactivity may help optimize test panel design.

Outdoor Alternaria and Cladosporium spores and acute asthma

BACKGROUND

Outdoor Alternaria and Cladosporium spores are ubiquitous. Few studies have assessed their impact on asthma hospitalizations providing conflicting results, mainly focused on vulnerable paediatric populations. We aimed to study the impact of outdoor Alternaria and Cladosporium concentrations on acute hospitalizations in the Capital Region of Denmark.

METHODS

This is a bi-directional case-crossover study with 26 years of national registry data at individual level on acute asthma hospitalizations and daily average data on Alternaria and Cladosporium, pollen (Artemisia, Poaceae), maximal temperature, and air pollution. Conditional logistic regression models were applied to assess the associations. Concentration quartiles at lag 0 were used for categorizing the exposure.

RESULTS

For lags 0-2, the odds of hospitalization were significantly higher for both Alternaria and Cladosporium at concentration quartile 2-4 compared with quartile 1. When stratified for age and sex, odds of hospitalization at Alternaria quartiles 2-4 were significantly higher in males below 40 years at lag 0-2, and at lag 0 in females (18-30 years), while quartiles 2-4 of Cladosporium concentrations were associated with significantly higher odds in boys (0-17 years) at lag 1-3, males (18-39 years) at lag 0-1, females (18-39 years) at lag 1-2, males (40-64 years) at lag 0-2, females (40-64 years) at lag 0 and 2, in seniors (65+ years) male at lag 1-2 and female at lag 0-1. The effect of Alternaria varied significantly depending on the level of Cladosporium (p < .0001).

CONCLUSION

Ambient Alternaria and Cladosporium spores can induce asthma hospitalizations. Males are more susceptible to both genera. Males and females under age 40 years are more susceptible to Alternaria.

Allergy immunotherapy for allergic fungal respiratory diseases

Background: Allergy immunotherapy (AIT) with fungal extracts is not as straight forward as that with other inhalants. The complexities relate to the number of airborne fungal spores, the limited data on the exposure to the spores of individual species of fungi and their clinical importance, the poor quality of the fungal allergen extracts that are available for the diagnosis and treatment, and the lack of controlled studies establishing dosing and efficacy of AIT with fungal extracts except for Alternaria. Objective: The objective was to review what is known with regard to the role of fungi in causing allergic respiratory diseases as well as the evidence that exists for the role of AIT as a treatment for these conditions. Methods: A search was conducted of PubMed, textbooks, known articles on immunotherapy with fungal extracts, and references derived from these primary sources. Results: Nine immunotherapy studies that used Alternaria or its major allergen Alt a 1 and two studies that used Cladosporium herbarum were identified. When a good quality extract was administered in adequate doses, immunotherapy with Alternaria was as effective as that with other inhalant allergens. There was a suggestion of efficacy with a specially prepared Cladosporium extract, but systemic reactions were common and limited the tolerated dose. The use of immunotherapy as an adjunct treatment for allergic fungal sinusitis is briefly reviewed, but controlled trials are lacking. Conclusion: Fungal immunotherapy should largely be limited to Alternaria alternata and perhaps C. herbarum. Under conditions of demonstrated exposure to a particular species of fungus and with symptoms that correlate with that exposure as well as availability of an apparently potent extract of that fungus to which the patient is sensitive that fungus may be considered for immunotherapy. Fungal (mold) mixes should not be used for diagnosis or therapy.

Monitoring of airborne fungi during the second wave of COVID-19 in selected wards of the referral university hospital in southeastern Iran

Microbiological monitoring of the air hospital is essential for prevention and control, due to the possible airborne route of infection transmission, especially in high-risk wards. This study aimed to monitor the airborne fungi during the second wave of the COVID-19 pandemic in selected wards of the biggest university educational hospital in Kerman, southeastern Iran. This study was conducted in 11 different wards, separated into the patient room and nursing station, of the Afzalipour hospital from May to August 2021. Fungal isolates were characterized to the species level by conventional and sequencing methods. Out of 93 obtained fungal colonies, 70 (75.3%) isolates were filamentous and 23 (24.7%) isolates were yeast. Aspergillus species were the predominant fungal isolates among the filamentous colonies (n=19; 27.1%), and Naganishia albida (formerly Cryptococcus albidus) was identified as the most common yeast isolate (n=13/23; 56.8%). The infectious ward was the most contaminated unit (n=19/93), while the least contaminated units were the neonatal intensive care unit (n=3/93), and oncology (n=3/93). The statistical findings displayed that the number of fungal isolates in patients' rooms is significantly higher than in nurses' stations (p-value=0.013). Our study demonstrated the presence of diverse fungal species in all wards of the hospital. Considering the presence of airborne fungi in hospitals and related public health problems is one of the critical issues for health systems management. In this regard, efficient monitoring of airborne fungi might play an influential role in hospital infection control and surveillance, particularly in high-risk hospitalization patients in critical wards.

Divergent TLR2 and TLR4 Activation by Fungal Spores and Species Diversity in Dust from Waste Sorting Plants

This manuscript presents the results of an exploratory study on the relationships between NF-κB response through Toll-like receptor (TLR) activation by dust characterized by fungal spore concentrations and species diversity. Personal total dust samples were collected from Norwegian waste sorting plants and then characterized for fungal spores and fungal species diversity, as well as for other bioaerosol components, including endotoxins and actinobacteria. The ability of the dust to induce an NF-κB response by activating TLR2 and TLR4 in vitro was evaluated, as well as the relationship between such responses and quantifiable bioaerosol components. The average concentrations of bioaerosols were 7.23 mg total dust m^-3, 4.49 × 10⁵ fungal spores m^-3, 814 endotoxin units m^-3, and 0.6 × 10⁵ actinobacteria m^-3. The mean diversity measurements were 326, 0.59, and 3.39 for fungal richness, evenness, and Shannon index, respectively. Overall, fungal operational taxonomic units (OTUs) belonging to the Ascomycota phylum were most abundant (55%), followed by Basidiomycota (33%) and Mucoromycota (3%). All samples induced significant NF-κB responses through TLR2 and TLR4 activation. While fungal spore levels were positively associated with TLR2 and TLR4 activation, there was a trend that fungal species richness was negatively associated with the activation of these receptors. This observation supports the existence of divergent immunological response relationships between TLR activation and fungal spore levels on one hand and between TLR activation and fungal species diversity on the other. Such relationships seem to be described for the first time for dust from waste facilities. IMPORTANCE This manuscript presents results on multifactorial characterization of bioaerosol exposure in Norwegian waste sorting plants and the potential of such airborne dust to induce NF-κB reactions through TLR2 and TLR4 activations in an in vitro reporter cell model system. Our data revealed that increasing fungal spore levels in the dust is associated with increased activation of TLR2 and TLR4, whereas increasing fungal OTU richness is associated with decreasing activation of these receptors. The NF-κB-induced responses by the collected dust represent, therefore, effective measures of potential key immunological effects induced by a complex mixture of hazardous components, including characterized factors such as endotoxins, fungal spores, bacteria, and many other uncharacterized components. The key immunological events reported here are suggested as holistic alternatives to today's bioaerosol exposure characterization approaches for epidemiological studies in the future.

Effects of fungal based bioactive compounds on human health: Review paper

Since the first years of history, microbial fermentation products such as bread, wine, yogurt and vinegar have always been noteworthy regarding their nutritional and health effects. Similarly, mushrooms have been a valuable food product in point of both nutrition and medicine due to their rich chemical components. Alternatively, filamentous fungi, which can be easier to produce, play an active role in the synthesis of some bioactive compounds, which are also important for health, as well as being rich in protein content. Therefore, this review presents some important bioactive compounds (bioactive peptides, chitin/chitosan, β-glucan, gamma-aminobutyric acid, L-carnitine, ergosterol and fructooligosaccharides) synthesized by fungal strains and their health benefits. In addition, potential probiotic- and prebiotic fungi were researched to determine their effects on gut microbiota. The current uses of fungal based bioactive compounds for cancer treatment were also discussed. The use of fungal strains in the food industry, especially to develop innovative food production, has been seen as promising microorganisms in obtaining healthy and nutritious food.

Persisting Cryptococcus yeast species Vishniacozyma victoriae and Cryptococcus neoformans elicit unique airway inflammation in mice following repeated exposure

Background

Allergic airway disease (AAD) is a growing concern in industrialized nations and can be influenced by fungal exposures. Basidiomycota yeast species such as Cryptococcus neoformans are known to exacerbate allergic airway disease; however, recent indoor assessments have identified other Basidiomycota yeasts, including Vishniacozyma victoriae (syn. Cryptococcus victoriae), to be prevalent and potentially associated with asthma. Until now, the murine pulmonary immune response to repeated V. victoriae exposure was previously unexplored.

Objective

This study aimed to compare the immunological impact of repeated pulmonary exposure to Cryptococcus yeasts.

Methods

Mice were repeatedly exposed to an immunogenic dose of C. neoformans or V. victoriae via oropharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) and lungs were collected to examine airway remodeling, inflammation, mucous production, cellular influx, and cytokine responses at 1 day and 21 days post final exposure. The responses to C. neoformans and V. victoriae were analyzed and compared.

Results

Following repeated exposure, both C. neoformans and V. victoriae cells were still detectable in the lungs 21 days post final exposure. Repeated C. neoformans exposure initiated myeloid and lymphoid cellular infiltration into the lung that worsened over time, as well as an IL-4 and IL-5 response compared to PBS-exposed controls. In contrast, repeated V. victoriae exposure induced a strong CD4+ T cell-driven lymphoid response that started to resolve by 21 days post final exposure.

Discussion

C. neoformans remained in the lungs and exacerbated the pulmonary immune responses as expected following repeated exposure. The persistence of V. victoriae in the lung and strong lymphoid response following repeated exposure were unexpected given its lack of reported involvement in AAD. Given the abundance in indoor environments and industrial utilization of V. victoriae, these results highlight the importance to investigate the impact of frequently detected fungal organisms on the pulmonary response following inhalational exposure. Moreover, it is important to continue to address the knowledge gap involving Basidiomycota yeasts and their impact on AAD.

Co-occurrence of airborne biological and anthropogenic pollutants in the central European urban ecosystem

The interactions between organic and inorganic air pollutants, enhanced by the impact of weather parameters, may worsen the respiratory allergy symptoms in allergy sufferers. Pollen grains and fungal spores belong to some of the most crucial aeroallergens. Other allergenic bioparticles in the atmospheric microbiome can include microalgae, fern spores and mites. In this study, we evaluated if and to what extent air pollutants and weather parameters drive the daily variation in airborne concentrations of broad spectrum of bioparticles (pollen grains, fungal spores, microalgae, fern spores and invertebrates) in the air of Bratislava over 3 years, 2019-2021. Air samples were collected using a Hirst-type volumetric sampler. Based on the results of Spearman's correlation analysis, air temperature seems to be the most influential meteorological factor, positively associated with the concentration of all types of bioparticles at assemblage level, even though the association with microalgae was negative. Wind speed, known to have a diluting effect on most airborne particles, appears to be the most influential for microalgae, as their concentration in the air increases along with rising wind speed. Considering air pollutants, correlation analysis revealed that as the daily concentrations of ozone, PM10, CO and/or NO2 increased, so did the levels of most types of analysed bioaerosols at the assemblage level. Regarding that bioparticles may act as carriers for inorganic particles and amplify their allergenic impact, a concomitant increment in the airborne concentration of both organic and inorganic pollutants poses a threat to allergy sufferers in the study area. The concentration of microalgae, on the other hand, decreases with rising levels of CO, NO2 and PM10; thereby, their synergistic effect on allergy sufferers is negligible. Based on our findings, we suggest that the response of pollen and fungal spore concentration to environmental conditions should be investigated at the taxon, not the assemblage level, as each pollen/spore taxon has a different pattern in response to meteorological parameters and air pollutants.

Fungal exposome, human health, and unmet needs: A 2022 update with special focus on allergy

Humans inhale, ingest, and touch thousands of fungi each day. The ubiquity and diversity of the fungal kingdom, reflected by its complex taxonomy, are in sharp contrast with our scarce knowledge about its distribution, pathogenic effects, and effective interventions at the environmental and individual levels. Here, we present an overview of salient features of fungi as permanent players of the human exposome and key determinants of human health, through the lens of fungal allergy and other fungal hypersensitivity reactions. Improved understanding of the fungal exposome sheds new light on the epidemiology of fungal-related hypersensitivity diseases, their immunological substratum, the currently available methods, and biomarkers for environmental and medical fungi. Unmet needs are described and potential approaches are highlighted as perspectives.

Recent Advances in the Allergic Cross-Reactivity between Fungi and Foods

Airborne fungi are one of the most ubiquitous kinds of inhalant allergens which can result in allergic diseases. Fungi tend to grow in warm and humid environments with regional and seasonal variations. Their nomenclature and taxonomy are related to the sensitization of immunoglobulin E (IgE). Allergic cross-reactivity among different fungal species appears to be widely existing. Fungus-related foods, such as edible mushrooms, mycoprotein, and fermented foods by fungi, can often induce to fungus food allergy syndrome (FFAS) by allergic cross-reactivity with airborne fungi. FFAS may involve one or more target organs, including the oral mucosa, the skin, the gastrointestinal and respiratory tracts, and the cardiovascular system, with various allergic symptoms ranging from oral allergy syndrome (OAS) to severe anaphylaxis. This article reviews the current knowledge on the field of allergic cross-reactivity between fungal allergens and related foods, as well as the diagnosis and treatment on FFAS.

Soil microbiota associated with immune-mediated disease was influenced by heavy metal stress in roadside soils of Shanghai

Heavy metals (HMs) and total petroleum hydrocarbons (TPHs) in soils can be detrimental to both soil microorganisms and public health. However, the effects of HMs and TPHs on microbes as well as the consequent microbial-derived health risk remains unclear in soils by local roads where citizens are clearly accessible to traffic-derived pollutants. Herein, we sampled 84 roadside soils throughout Shanghai. We measured the levels of soil edaphic factors, 6 HMs, and alkane TPHs. We further focused on the responses of bacterial and fungal communities assessed via sequencing and network analysis. Results showed that all soil HMs exceeded background levels of Shanghai soil, while the levels of TPHs are comparable to unpolluted sites. Bacterial network nodes and links decreased sharply under HM stress whereas that of fungal networks remained unchanged. The differential pattern was attributed to the asynchronous response of key classes that fungal key classes were more resistant to HMs than bacteria. In addition, 66.8 % of fungal genera associated with immune-mediated disease increased with increased HM stress for its HM tolerance. Together our findings indicate that despite the relatively stable fungal community in response to environmental stresses, the elevation of harmful fungi likely pose threats to health of urban dwellers.

Fungal Spore Richness in School Classrooms is Related to Surrounding Forest in a Season-Dependent Manner

Airborne fungal spores are important aeroallergens that are remarkably diverse in terms of taxonomic richness. Indoor fungal richness is dominated by outdoor fungi and is geographically patterned, but the influence of natural landscape is unclear. We aimed to elucidate the relationship between indoor fungal spore richness and natural landscape by examining the amount of surrounding forest cover. Passive sampling of airborne fungal spores was conducted in 24 schools in Taiwan during hot and cool seasons, and amplicon sequencing was used to study fungal spore (genus) richness targeting the internal transcribed spacer 2 (ITS2) region. In total, 693 fungal genera were identified, 12 of which were ubiquitous. Despite overall similarity of fungal spore richness between seasons, Basidiomycota and Ascomycota richness increased during the hot and cool seasons, respectively. Fungal spore richness in schools had a strong positive correlation with the amount of surrounding forest cover during the cool season, but not during the hot season. Fungal assemblages in schools were more similar during the hot season due to the increased ubiquity of Agaricomycetes genera. These observations indicate dispersal limitation at the kilometer scale during the cool season and increased long-distance dispersal during the hot season. Several allergenic fungi were commonly identified in schools, including some previously overlooked by conventional methods, which may be targeted as sensitizing agents in future investigations into atopic conditions. More generally, the relative importance of fungal spore richness in the development, chronicity, and severity of atopic conditions in children requires investigation.

Aspergillus Hydrophobins: Physicochemical Properties, Biochemical Properties, and Functions in Solid Polymer Degradation

Hydrophobins are small amphipathic proteins conserved in filamentous fungi. In this review, the properties and functions of Aspergillus hydrophobins are comprehensively discussed on the basis of recent findings. Multiple Aspergillus hydrophobins have been identified and categorized in conventional class I and two non-conventional classes. Some Aspergillus hydrophobins can be purified in a water phase without organic solvents. Class I hydrophobins of Aspergilli self-assemble to form amphipathic membranes. At the air–liquid interface, RolA of Aspergillus oryzae self-assembles via four stages, and its self-assembled films consist of two layers, a rodlet membrane facing air and rod-like structures facing liquid. The self-assembly depends mainly on hydrophobin conformation and solution pH. Cys4–Cys5 and Cys7–Cys8 loops, disulfide bonds, and conserved Cys residues of RodA-like hydrophobins are necessary for self-assembly at the interface and for adsorption to solid surfaces. AfRodA helps Aspergillus fumigatus to evade recognition by the host immune system. RodA-like hydrophobins recruit cutinases to promote the hydrolysis of aliphatic polyesters. This mechanism appears to be conserved in Aspergillus and other filamentous fungi, and may be beneficial for their growth. Aspergilli produce various small secreted proteins (SSPs) including hydrophobins, hydrophobic surface–binding proteins, and effector proteins. Aspergilli may use a wide variety of SSPs to decompose solid polymers.

A review of toxigenic fungi and mycotoxins in feeds and food commodities in West Africa

Fungal contamination is a threat to food safety in West Africa with implications for food and feed due to their climate, which is characterised by high temperatures and high relative humidity, which are environmental favourable for fast fungal growth and mycotoxin production. This report gives perspective on studies on toxigenic fungi (Aspergillus, Fusarium and Penicillium) and their toxins, mainly aflatoxins, fumonisins and ochratoxins commonly found in some West African countries, including Benin, Burkina Faso, Gambia, Ghana, Ivory Coast, Mali, Nigeria, Senegal, Sierra Leone, and Togo. Only four of these countries have mycotoxins regulations in place for feeds and food products (Ghana, Ivory Coast, Nigeria, and Senegal). Food commodities that are widely consumed and were thoroughly investigated in this region include cereals, peanuts, cassava chips (flakes), cassava flour, chilies, peanuts, locust beans, melon, and yam products. In conclusion, authorities and scientists needed to consider research and approaches to monitor mycotoxins in foods and feeds produced and consumed in West Africa.

Diversity and Metabolic Activity of Fungi Causing Biodeterioration of Canvas Paintings

Research into the biodeteriorative potential of fungi can serve as an indicator of the condition of heritage items. Biodeterioration of canvas paintings as a result of fungal metabolic activity is understudied with respect to both the species diversity and mechanisms involved. This study brings new evidence for the physiology of fungi biodeteriorative capacity of canvas paintings. Twenty-one fungal isolates were recovered from four oil paintings (The Art Museum, Cluj-Napoca) and one gouache painting (private collection), dating from the 18th to 20th centuries. The species, identified based on the molecular markers Internal Transcribed Spacer (ITS), beta-tubulin (tub2), or translation elongation factor 1 (TEF-1), are common colonisers of canvas paintings or indoor environments (e.g., Penicillium spp., Aspergillus spp., Alternaria spp.). Fungi enzymatic profiles were investigated by means of hydrolysable substrates, included in culture media or in test strips, containing components commonly used in canvas paintings. The pigment solubilisation capacity was assessed in culture media for the primary pigments and studied in relation to the organic acid secretion. Caseinases, amylases, gelatinases, acid phosphatase, N-acetyl-β-glucosaminidase, naphthol-AS-BI-phosphohydrolase, and β-glucosidase were found to be the enzymes most likely involved in the processes of substrate colonisation and breakdown of its components. Aureobasidium genus was found to hold the strongest biodeteriorative potential, followed by Cladosporium, Penicillium, Trichoderma, and Aspergillus. Blue pigment solubilisation was detected, occurring as a result of organic acids secretion. Distinct clusters were delineated considering the metabolic activities detected, indicating that fungi specialise in utilisation of certain types of substrates. It was found that both aged and modern artworks are at risk of fungal biodeterioration, due to the enzymatic activities’ diversity and intensity, pigment solubilisation capacity or pigment secretion.

Misalignment between Clinical Mold Antigen Extracts and Airborne Molds Found in Water-Damaged Homes

RATIONALE

Epidemiologic studies have demonstrated that exposure to molds and other fungi can play a role in a variety of allergic and pulmonary diseases in susceptible individuals. Species-specific mold antigen extracts are used in the clinical evaluation of suspected mold-related conditions, however alignment between these extracts and the species of molds identified in the indoor environment of water-damaged homes has not been rigorously evaluated.

OBJECTIVES

To identify the predominant genera and species of mold in the air of homes with water damage, mold growth, and/or occupants with respiratory complaints (complaint homes), and to assess their alignment with the mold antigen extracts used in clinical practice.

METHODS

The genera and species of molds identified in culture-type outdoor and indoor air samples collected from complaint homes throughout the U.S. and Canada from 2002-2017 were examined. Mold antigen extracts available and utilized for skin and serum testing in clinical practice were assessed and alignment between these data were evaluated.

RESULTS

Culture data from 24,455 indoor air samples from 7,547 complaint homes and 29,493 outdoor samples was evaluated. Mean exposure values (CFU/m3) were calculated for each genus and species, and indoor vs outdoor values compared. Penicillium was the predominant genus identified in water-damaged homes, with a mean exposure (233.3 CFU/m3) 2.9 times higher than that of the Aspergillus genus (81.4 CFU/m3). Five Penicillium (P. aurantiogriseum, P. brevicompactum, P. citrinum, P. crustosum, and P. variabile) and three Aspergillus (A. versicolor, A. sydowii, and A. niger) species were identified as the predominant indoor water-damage related fungi. However, none of these Penicillium species and only one of the Aspergillus species is currently available as an antigen extract for use in skin testing or serum testing panels.

CONCLUSIONS

Significant misalignment exists between the currently available mold antigen extracts and the predominant species of molds found in water-damaged homes. Improving alignment has the potential to enhance diagnosis of mold-related diseases including allergic asthma and hypersensitivity pneumonitis and to improve patient outcomes via interventions including antigen avoidance through building remediation and occupant relocation, consistent with the findings of a recent ATS Workshop Report.

Fungal populations in the bedroom dust of children in Havana, Cuba, and its relationship with environmental conditions

The study of the fungal community composition in house dust is useful to assess the accumulative exposure to fungi in indoor environments. The objective of this research was to characterize the fungal diversity of house dust and its association with the environmental conditions of bedrooms. For this, the dust was collected from 41 bedrooms of children between the ages of 8 and 9 with a family history of asthma, residents of Havana, Cuba. The fungal content of each sample was determined by two methods: plate culture with malt extract agar and by direct microscopy. An ecological analysis was carried out from the fungal diversity detected. To describe the factors associated with the fungi detected, bivariate logistic regression was used. Through direct microscopy, between 10 and 2311 fragments of hyphae and spores corresponding mainly to Cladosporium, Coprinus, Curvularia, Aspergillus/Penicillium, Xylariaceae, and Periconia were identified. Through the culture, 0-208 CFU were quantified, where Aspergillus, Cladosporium, and Penicillium predominated. The culturability evidenced the differences between the quantification determined by both methods. A positive relationship was found between the type of cleaning of the furniture, the presence of trees in front of the bedroom, indoor relative humidity, indoor temperature, the presence of air conditioning, and natural ventilation with specific spore types and genera. The use of two different identification methods allowed to detect a greater fungal diversity in the residences evaluated. Monitoring the exposure to these fungal allergens in childhood can help to prevent sensitization in the allergic child, the development of asthma, and other respiratory diseases.

Mycosands: Fungal diversity and abundance in beach sand and recreational waters - Relevance to human health

The goal of most studies published on sand contaminants is to gather and discuss knowledge to avoid faecal contamination of water by run-offs and tide-retractions. Other life forms in the sand, however, are seldom studied but always pointed out as relevant. The Mycosands initiative was created to generate data on fungi in beach sands and waters, of both coastal and freshwater inland bathing sites. A team of medical mycologists and water quality specialists explored the sand culturable mycobiota of 91 bathing sites, and water of 67 of these, spanning from the Atlantic to the Eastern Mediterranean coasts, including the Italian lakes and the Adriatic, Baltic, and Black Seas. Sydney (Australia) was also included in the study. Thirteen countries took part in the initiative. The present study considered several fungal parameters (all fungi, several species of the genus Aspergillus and Candida and the genera themselves, plus other yeasts, allergenic fungi, dematiaceous fungi and dermatophytes). The study considered four variables that the team expected would influence the results of the analytical parameters, such as coast or inland location, urban and non-urban sites, period of the year, geographical proximity and type of sediment. The genera most frequently found were Aspergillus spp., Candida spp., Fusarium spp. and Cryptococcus spp. both in sand and in water. A site-blind median was found to be 89 Colony-Forming Units (CFU) of fungi per gram of sand in coastal and inland freshwaters, with variability between 0 and 6400 CFU/g. For freshwater sites, that number was 201.7 CFU/g (0, 6400 CFU/g (p = 0.01)) and for coastal sites was 76.7 CFU/g (0, 3497.5 CFU/g). For coastal waters and all waters, the median was 0 CFU/ml (0, 1592 CFU/ml) and for freshwaters 6.7 (0, 310.0) CFU/ml (p < 0.001). The results advocate that beaches should be monitored for fungi for safer use and better management.

Airborne fungi in Universiti Sains Malaysia: knowledge, density and diversity

Airborne fungi are among common contaminants in indoor and outdoor environments, leading to poor indoor air quality (IAQ), and to some extent, implicate health risks to humans worldwide. In Malaysia, fungal contamination in institutional buildings is rarely documented although these places are frequently visited by many. This study was conducted to assess the density and diversity of airborne fungi in Universiti Sains Malaysia (USM) main campus, Penang. A total of 11 sampling sites were assessed. Fungi were collected by using Andersen Single Stage Impact Air Sampler N-6 and MEA plates. Two separate trials, namely Trial 1 and Trial 2, were conducted in 2008 and 2019, respectively. The recovered fungi were identified up to the genus level-based morphological features. A survey involving 400 respondents among USM staff and students in relation to fungal contamination in indoor air environment was also conducted to evaluate the knowledge on indoor fungi among USM community. The densities of indoor air fungi in Trial 1 were higher; ranging from 81 to 1743 CFU/m³, exceeding the recommended level set by the Malaysia Industry Code of Practice (MCPIAQ) in some sampling sites, compared to that of in Trial 2 where the densities ranged from 229 to 699 CFU/m³. A total of 154 isolates and 230 isolates of airborne fungi were recovered in Trial 1 and Trial 2, respectively. In total, 11 fungal genera were identified in both trials, and three genera were predominant: Aspergillus, Penicillium, and Cladosporium. The survey also revealed that knowledge of IAQ among staff and students was limited and that they were unaware of fungal contamination and IAQ. A continuous and wide-spread awareness should be implemented at USM main campus for safer and healthier indoor air environments, particularly university students where productivity and efficiency are of the utmost importance.

Associations between the spatiotemporal distribution of Kawasaki disease and environmental factors: evidence supporting a multifactorial etiologic model

The etiology of Kawasaki Disease (KD), the most common cause of acquired heart disease in children in developed countries, remains elusive, but could be multifactorial in nature as suggested by the numerous environmental and infectious exposures that have previously been linked to its epidemiology. There is still a lack of a comprehensive model describing these complex associations. We present a Bayesian disease model that provides insight in the spatiotemporal distribution of KD in Canada from 2004 to 2017. The disease model including environmental factors had improved Watanabe-Akaike information criterion (WAIC) compared to the base model which included only spatiotemporal and demographic effects and had excellent performance in recapitulating the spatiotemporal distribution of KD in Canada (98% and 86% spatial and temporal correlations, respectively). The model suggests an association between the distribution of KD and population composition, weather-related factors, aeroallergen exposure, pollution, atmospheric concentration of spores and algae, and the incidence of healthcare encounters for bacterial pneumonia or viral intestinal infections. This model could be the basis of a hypothetical data-driven framework for the spatiotemporal distribution of KD. It also generates novel hypotheses about the etiology of KD, and provides a basis for the future development of a predictive and surveillance model.

Allergic fungal airways disease (AFAD): an under-recognised asthma endotype

The term allergic fungal airways disease has a liberal definition based on IgE sensitisation to thermotolerant fungi and evidence of fungal-related lung damage. It arose from a body of work looking into the role of fungi in asthma. Historically fungi were considered a rare complication of asthma, exemplified by allergic bronchopulmonary aspergillosis; however, there is a significant proportion of individuals with Aspergillus fumigatus sensitisation who do not meet these criteria, who are at high risk for the development of lung damage. The fungi that play a role in asthma can be divided into two groups; those that can grow at body temperature referred to as thermotolerant, which are capable of both infection and allergy, and those that cannot but can still act as allergens in IgE sensitised individuals. Sensitisation to thermotolerant filamentous fungi (Aspergillus and Penicillium), and not non-thermotolerant fungi (Alternaria and Cladosporium) is associated with lower lung function and radiological abnormalities (bronchiectasis, tree-in-bud, fleeting shadows, collapse/consolidation and fibrosis). For antifungals to play a role in treatment, the focus should be on fungi capable of growing in the airways thereby causing a persistent chronic allergenic stimulus and releasing tissue damaging proteases and other enzymes which may disrupt the airway epithelial barrier and cause mucosal damage and airway remodelling. All patients with IgE sensitisation to thermotolerant fungi in the context of asthma and other airway disease are at risk of progressive lung damage, and as such should be monitored closely.

Species distribution and antifungal susceptibilities of clinical isolates of Penicillium and Talaromyces species in China

Morphologically identified Penicillium (n = 103) and Talaromyces marneffei (n = 8) isolates were collected from various clinical sources between 2016 and 2017 at a medical centre in Beijing, China. Identification to species level was confirmed by sequencing of the internal transcribed spacer (ITS) region, β-tubulin gene (benA) and RNA polymerase II second largest subunit (RPB2) gene. Of the 111 isolates, 56 (50.5%) were identified as Penicillium spp. and 55 (49.5%) as Talaromyces spp. Eleven species of Penicillium were detected, of which Penicillium oxalicum was the commonest, accounting for 51.8% (29/56), followed by Penicillium rubens (10.7%; 6/56) and Penicillium citrinum (10.7%; 6/56). Among the 55 Talaromyces isolates, nine species were identified, with Talaromyces funiculosus (36.4%; 20/55), Talaromyces stollii (27.3%; 15/55) and Talaromyces marneffei (14.5%; 8/55) being the most common. Of note, 89.3% (50/56) of the Penicillium isolates and 98.2% (54/55) of the Talaromyces isolates exhibited growth at 37°C. The isolates were mainly recovered from patients with pulmonary disorders (56.8%; 63/111), autoimmune disease (12.6%; 14/111) and AIDS (5.4%; 6/111). The azoles and amphotericin B exhibited potent activity against T. marneffei, while various levels of activity were observed against Penicillium and other Talaromyces species The echinocandins had the lowest MECs (MEC_90, ≤0.12 mg/L) against most Penicillium and Talaromyces species, with the exception of T. marneffei whose MEC₉₀ (4 mg/L) was five or more dilutions higher than that of the other species tested. These data on the species distribution and antifungal susceptibility expand the current clinical knowledge of Penicillium and Talaromyces species.

Sensitization against Fungi in Patients with Airway Allergies over 20 Years in Germany

BACKGROUND

Fungal spores are ubiquitous allergens. Severe forms of asthma are particularly highly associated with fungal sensitization. National and international asthma guidelines recommend the implementation of allergen immunotherapy if indicated. Thus, detection and treatment of relevant allergies are key components of primary care of these patients.

OBJECTIVES

The aims of the study were (i) to investigate trends in the prevalence of sensitization to twelve fungi in central Germany over the last 20 years and (ii) to dissect specific sensitization patterns among the 3 most important fungi: Aspergillus, Alternaria, and Cladosporium.

METHODS

This single-center study evaluated skin prick test (SPT) results of 3,358 patients with suspected airway allergies over a period of 20 years (1998-2017).

RESULTS

While 19.2% of all study patients had positive test results to at least 1 of the 3 fungi (Alternaria, Aspergillus, or Cladosporium) in the first study decade, this rate increased to 22.5% in the second decade. Slight increases in sensitization rates to almost all fungi were observed over the 20-year period. In the last decade, polysensitization to Alternaria, Aspergillus, and Cladosporium increased significantly. Sensitization to fungi is age-dependent and peaks in the age-group of 21-40 years during the second decade.

CONCLUSION

Fungi are relevant allergens for perennial and seasonal allergy symptoms. We currently recommend including Aspergillus, Alternaria, and Cladosporium in the standard series of SPTs for airway allergies.

Multipronged dental analyses reveal dietary differences in last foragers and first farmers at Grotta Continenza, central Italy (15,500-7000 BP)

This paper provides results from a suite of analyses made on human dental material from the Late Palaeolithic to Neolithic strata of the cave site of Grotta Continenza situated in the Fucino Basin of the Abruzzo region of central Italy. The available human remains from this site provide a unique possibility to study ways in which forager versus farmer lifeways affected human odonto-skeletal remains. The main aim of our study is to understand palaeodietary patterns and their changes over time as reflected in teeth. These analyses involve a review of metrics and oral pathologies, micro-fossils preserved in the mineralized dental plaque, macrowear, and buccal microwear. Our results suggest that these complementary approaches support the assumption about a critical change in dental conditions and status with the introduction of Neolithic foodstuff and habits. However, we warn that different methodologies applied here provide data at different scales of resolution for detecting such changes and a multipronged approach to the study of dental collections is needed for a more comprehensive and nuanced understanding of diachronic changes.

Fungal pathogens found in tissues of herbaceous plants growing in the Yereymentau District, Akmola region

The biocontrol programs that are currently developed focus on specific microorganisms that live in plant tissues, also known as the endophytes. This article discusses pathogenic micromycete species that infected herbaceous plants growing in the Yereymentau District, Akmola Region. Four fungi species were detected that belong to the same genus. Information about the species composition and a brief description of each fungus were provided. The seasonal behavior of rust fungi was investigated. As it turned out, rust fungi tend to go through the uredinium phase in July and to produce teliospores in September. The research population includes the most common species of rust fungi. This article was first to identify phytopathogenic fungi that attack herbaceous plants in the Yereymentau District and their seasonal behavior. The findings may contribute towards expanding the global fungal database with information about fungal diseases specific to the given region and towards combat against a variety of phytopathogenic fungi.

Asthma Prevalence and Mold Levels in US Northeastern Schools

BACKGROUND

Asthma is among the most common chronic diseases of children in the United States (US). Mold exposures have been linked to asthma development and exacerbation. In homes, mold exposures have been quantified using the Environmental Relative Moldiness Index (ERMI), and higher home ERMI values have been linked to occupant asthma.

OBJECTIVE

In this analysis of the School Inner-City Asthma Study (SICAS), we aimed to evaluate the ERMI's applicability to measuring mold in schools compared with homes and to examine the prevalence of asthma in relationship to students' demographics and the physical characteristics of school buildings.

METHODS

Northeastern US schools (n = 32) and homes (n = 33) were selected, and the 36 ERMI molds were quantified in a dust sample from each classroom (n = 114) or home. School building characteristics data were collected from SICAS. Asthma prevalence and student demographics data were obtained from government websites. Linear regression and mixed models were fit to assess the association of the current asthma prevalence and physical characteristics of the school, make-up of the student body, and the ERMI metric.

RESULTS

Levels of outdoor group 2 molds were significantly (P < .01) greater in schools compared with homes. The presence of air-conditioning in school buildings correlated significantly (P = .02) with lower asthma prevalence.

CONCLUSION

The prevalence of asthma in student bodies is associated with many factors in schools and homes.

Investigating the culturable atmospheric fungal and bacterial microbiome in West Texas: implication of dust storms and origins of the air parcels

Individuals often experience ailments such as allergies, asthma and respiratory tract infections throughout the year. Weather reports often include estimations of common allergens that can affect these individuals. To describe the local 'atmospheric microbiome' in Lubbock, Texas, USA, we examined the culturable fungal and bacterial microbiome present in the air on calm and dust storm days using internal transcribed spacer (ITS)-1 and 16S rRNA amplicon sequencing, respectively. While some types of airborne fungi were frequently present throughout the year, distinct differences were also observed between calm and dust storm days. We also observed the influence of the origin of air parcels and wind elevation of the air trajectory. The most abundant genera of fungi identified during the study period were Cryptococcus, Aureobasidium, Alternaria, Cladosporium and Filobasidium. This observation was not surprising considering the agricultural intensive environment of West Texas. Interestingly, Cladosporium, a common allergenic mold, was increased during days with dust storm events. The predominant bacterial genera observed were Bacillus, Pseudomonas, Psychrobacter, Massilia and Exiguobacterium. The relative abundance of the psychrophiles, Psychrobacter and Exiguobacterium, was surprising, given the semi-aridity of West Texas. Coupling our observations with back trajectories of the wind (Hybrid Single-Particle Lagrangian Integrated Trajectory models) demonstrated that dust storms, regional anthropogenic activity and origin of air parcels are important influences on the diversity and temporal presence of the atmospheric microbiome.

Mass Spectrometry: A Rosetta Stone to Learn How Fungi Interact and Talk

Fungi are a highly diverse group of heterotrophic organisms that play an important role in diverse ecological interactions, many of which are chemically mediated. Fungi have a very versatile metabolism, which allows them to synthesize a large number of still little-known chemical compounds, such as soluble compounds that are secreted into the medium and volatile compounds that are chemical mediators over short and long distances. Mass spectrometry (MS) is currently playing a dominant role in mycological studies, mainly due to its inherent sensitivity and rapid identification capabilities of different metabolites. Furthermore, MS has also been used as a reliable and accurate tool for fungi identification (i.e., biotyping). Here, we introduce the readers about fungal specialized metabolites, their role in ecological interactions and provide an overview on the MS-based techniques used in fungal studies. We particularly present the importance of sampling techniques, strategies to reduce false-positive identification and new MS-based analytical strategies that can be used in mycological studies, further expanding the use of MS in broader applications. Therefore, we foresee a bright future for mass spectrometry-based research in the field of mycology.

The allergenic activity and clinical impact of individual IgE-antibody binding molecules from indoor allergen sources

A large number of allergens have been discovered but we know little about their potential to induce inflammation (allergenic activity) and symptoms. Nowadays, the clinical importance of allergens is determined by the frequency and intensity of their IgE antibody binding (allergenicity). This is a rather limited parameter considering the development of experimental allergology in the last 20 years and the criteria that support personalized medicine. Now it is known that some allergens, in addition to their IgE antibody binding properties, can induce inflammation through non IgE mediated pathways, which can increase their allergenic activity. There are several ways to evaluate the allergenic activity, among them the provocation tests, the demonstration of non-IgE mediated pathways of inflammation, case control studies of IgE-binding frequencies, and animal models of respiratory allergy. In this review we have explored the current status of basic and clinical research on allergenic activity of indoor allergens and confirm that, for most of them, this important property has not been investigated. However, during recent years important advances have been made in the field, and we conclude that for at least the following, allergenic activity has been demonstrated: Der p 1, Der p 2, Der p 5 and Blo t 5 from HDMs; Per a 10 from P. americana; Asp f 1, Asp f 2, Asp f 3, Asp f 4 and Asp f 6 from A. fumigatus; Mala s 8 and Mala s 13 from M. sympodialis; Alt a 1 from A. alternata; Pen c 13 from P. chrysogenum; Fel d 1 from cats; Can f 1, Can f 2, Can f 3, Can f 4 and Can f 5 from dogs; Mus m 1 from mice and Bos d 2 from cows. Defining the allergenic activity of other indoor IgE antibody binding molecules is necessary for a precision-medicine-oriented management of allergic diseases.

Fungi and Atopy

Atopy and fungi have a long associative history. Fungal spores were among the first substances to which humans were noted to be sensitized. Humans contact fungal spores in the outdoor, indoor, and occupational environments. As organisms, fungi have their own kingdom and are found in all environmental niches on earth. Currently, fungal exposure in the indoor environment especially related to wet housing conditions is of particular concern. Sensitization rates to fungi typically exceed 5% of the general public with higher rates among the atopic population. Alternaria is the best studied of the allergic fungi; however, cross sensitization to multiple fungi is well documented. Recent advances in understanding mechanisms of the innate immune system are beginning to explain why the fungal atopy relationship is unique and why fungal sensitivity seems to extend to many non-atopic individuals. Evidence has been accumulated that indicates fungal allergen exposure can be via intact spores as well as spore and mycelial fragments. Germinating spores produce a different and often increased allergen picture. Much evidence has been developed through animal studies that extends the mechanisms surrounding long-term low-level fungal exposure. However, it should be emphasized that the presence of fungi in the air does not necessarily equate with illness. Indeed, in the absence of an atopic individual and/or a significant immune response against fungi, there is little evidence suggesting pathology. Allergists frequently deal with patients who have concerns about indoor fungal exposure and respiratory disease in those patients with an allergic response.

Indoor Environmental Interventions for Furry Pet Allergens, Pest Allergens, and Mold: Looking to the Future

Over the last 2 to 3 decades, significant advances have been made in understanding the role that indoor allergen exposures play with regard to respiratory health. Multiple studies have confirmed that sensitization and exposure to indoor allergens can be a risk factor for asthma morbidity. Environmental interventions targeting key indoor allergens have been evaluated with the aims of examining their causal effects on asthma-related outcomes and identifying clinically efficacious interventions to incorporate into treatment recommendations. Historically, it appeared that the most successful intervention, as performed in the Inner-City Asthma Study, was individually tailored, targeting multiple allergens in a predominantly low-income, minority, and urban pediatric population. Recent studies suggest that single-allergen interventions may be efficacious when targeting the most clinically relevant allergen for a population. In this article, we review recent literature on home environmental interventions and their effects on specific indoor allergen levels and asthma-related outcomes.

Emerging Insights into the Occupational Mycobiome

PURPOSE OF REVIEW

The evolution of molecular-based methods over the last two decades has provided new approaches to identify and characterize fungal communities or "mycobiomes" at resolutions previously not possible using traditional hazard identification methods. The recent focus on fungal community assemblages within indoor environments has provided renewed insight into overlooked sources of fungal exposure. In occupational studies, internal transcribed spacer (ITS) region sequencing has recently been utilized in a variety of environments ranging from indoor office buildings to agricultural commodity and harvesting operations.

RECENT FINDINGS

Fungal communities identified in occupational environments have been primarily placed in the phylum Ascomycota and included classes typically identified using traditional fungal exposure methods such as the Eurotiomycetes, Dothideomycetes, Sordariomycetes, and Saccharomycetes. The phylum Basidiomycota has also been reported to be more prevalent than previously estimated and ITS region sequences have been primarily derived from the classes Agaricomycetes and Ustilaginomycetes. These studies have also resolved sequences placed in the Basidiomycota classes Tremellomycetes and Exobasidiomycetes that include environmental and endogenous yeast species. These collective datasets have shown that occupational fungal exposures include a much broader diversity of fungi than once thought. Although the clinical implications for occupational allergy are an emerging field of research, establishing the mycobiome in occupational environments will be critical for future studies to determine the complete spectrum of worker exposures to fungal bioaerosols and their impact on worker health.

Identification of saprophytic and allergenic fungi in indoor and outdoor environments

The airborne spores of some saprophytic and allergenic fungi such as Aspergillus, Alternaria, and Cladosporium are found throughout the world and exposure to these agents may result in various types of allergic diseases. The aim of this study, therefore, was to investigate the frequency of different saprophytic, allergenic, and pathogenic fungi in indoor and outdoor environments. During a 6-month period, 780 samples were obtained from a number of houses, mosques, parks, public restrooms, grocery stores, laboratories, and hospitals. An open-plate method was applied for air sampling by exposing 90-mm plates containing chloramphenicol/potato dextrose agar and malt extract agar were exposed to air for 30 min. Alternatively, the sampling from surfaces was performed using sterile wet swab and tape-stripe method. All samples were then inoculated in media and incubated at 28 °C for 2-3 weeks. The isolated fungi were purified in order to detect the genus, and if possible, species level of the targeted fungi based on morphological and microscopic features using standard methods. The findings revealed that the dominant indoor and outdoor fungal species were Aspergillus, Penicillium, and Cladosporium whose frequency values were 16.42%, 16.17%, and 14.92% respectively. The lowest frequency was related to Acrophialophora and Madurella (0.25%). More notably, the results for air and surface were similar. It was also found out that the three dominant genera were Aspergillus (16.53%), Penicillium (15.50%), and Cladosporium (11.93%), with Basidiobolus and Acrophialophora having the lowest frequency. It was observed that different environmental spaces have a great bearing on the spreading of such allergic agents, especially in subtropical humid climates.

Bedroom Allergen Exposure Beyond House Dust Mites

PURPOSE OF REVIEW

The review provides insight into recent findings on bedroom allergen exposures, primarily focusing on pet, pest, and fungal exposures.

RECENT FINDINGS

Large-scale studies and improved exposure assessment technologies, including measurement of airborne allergens and of multiple allergens simultaneously, have extended our understanding of indoor allergen exposures and their impact on allergic disease. Practical, streamlined methods for exposure reduction have shown promise in some settings, and potential protective effects of early-life exposures have been further elucidated through the investigation of specific bacterial taxa. Advances in molecular allergology have yielded novel data on sensitization profiles and cross-reactivity. The role of indoor allergen exposures in allergic disease is complex and remains incompletely understood. Advancing our knowledge of various co-exposures, including the environmental and host microbiome, that interact with allergens in early life will be crucial for the development of efficacious interventions to reduce the substantial economic and social burden of allergic diseases including asthma.

Aeroallergens in Canada: Distribution, Public Health Impacts, and Opportunities for Prevention

Aeroallergens occur naturally in the environment and are widely dispersed across Canada, yet their public health implications are not well-understood. This review intends to provide a scientific and public health-oriented perspective on aeroallergens in Canada: their distribution, health impacts, and new developments including the effects of climate change and the potential role of aeroallergens in the development of allergies and asthma. The review also describes anthropogenic effects on plant distribution and diversity, and how aeroallergens interact with other environmental elements, such as air pollution and weather events. Increased understanding of the relationships between aeroallergens and health will enhance our ability to provide accurate information, improve preventive measures and provide timely treatments for affected populations.