Search Results (30)

Urbanization has been suspected to increase the allergic rate of people, and its impact on airborne fungi and potential allergens has drawn attention. In this study, aerosol samples were collected concurrently at proximate urban and rural sites of Shanghai during the four seasons to analyze the changes in abundance and community composition of airborne fungi. In summer, there were significantly higher concentrations of fungi in the urban atmosphere compared to at the rural site. Ascomycota and Basidiomycota were the top two fungal phyla, and Cladosporium was the most abundant genus year round. Alternaria was the second highest genus in spring and winter (only the rural site), whereas Nigrospora ranked second during summer and autumn due to it largely being sourced from marine organisms and predominantly marine-influenced air masses in these seasons. Airborne fungal richness was relatively higher at the rural site than in urban during winter. Allergenic fungal species were found to be more abundant in winter than in other seasons; particularly, the relative abundance of Cladosporium sp. was significantly higher (p < 0.001), and Fusarium culmorum and Cladosporium herbarum also increased more in urban than in rural areas, which may be one of the key factors contributing to the rising allergic rate in the urban population. Full article

Background/Objectives: Long-term ventilation (LTV) is a widely used treatment for the management of patients with chronic respiratory failure. As use increases, it generates further questions about aspects of care. One issue is the potential risk of contamination within the device itself and the potential risk of respiratory tract infections in a subsequent user. Using an observational cross-sectional study design, the primary objective of this study was to identify whether airborne bacterial and fungal pathogens are present within a NIPPY 3+ (Breas Medical Ltd., Stratford Upon Avon, UK) room air ventilator following use in a community setting. Methods: Microbiological samples in the form of one single charcoal swab were taken from two specified areas of the device’s internal airflow pathway. Results: A total of 243 ventilators were sampled. A total of 215 ventilators with complete data collection were included in the study. A total of 84 (39%) were identified as having no growth and 131 (61%) were positive for bacterial and/or fungal growth. Overall, 307 organisms were grown from 131 ventilators ranging from 1 to 6 organisms per swab. Of the 215 ventilators screened, 15 (7%) grew organisms considered to be pathogenic. Well-established human pathogens were considered as ‘potentially pathogenic’ in this study due to the limitation of not obtaining patient-specific data, meaning host–pathogen interaction could not be determined. Of these, 14 grew one pathogenic organism and 1 grew four distinct pathogens. This is the largest study to date exploring the potential presence of airborne pathogens in room air ventilators. We have demonstrated that 61% of these devices were positive for bacterial or fungal growth and 7% were pathogenic. Pathogenic organisms included Pseudomonas aeruginosa, Staphylococcus aureus and Aspergillus sp. Although the growth of pathogenic organisms was relatively rare, there are important potential adverse clinical outcomes in patients with diseases commonly treated by LTV services. Conclusions: We have shown that the contamination of devices is rare, but, in 7%, there is contamination with potentially pathogenic organisms, which, if proven to be transferred between patients, could be a cause of worse patient outcomes. Full article

Airborne fungi are widely distributed in the environment and originate from various sources like soil, plants, decaying organic matter, and even indoor environments. Exposure to airborne fungal spores can cause allergic reactions, asthma, and respiratory infections. Certain fungi can cause serious infections, particularly in individuals with weakened immune systems. An aerobiological study was conducted to detect airborne fungi using metagenomics in three areas of Mexico City, each representing different degrees of urbanization, during the dry and rainy seasons of 2017. Seasonality showed a significant role in the composition of airborne fungi. Ascomycota predominated in the three areas sampled during dry and rainy seasons, with the genera Cladosporium and Penicillium presenting the highest relative abundances across seasons. The Agaromycetes showed an increase during the rainy season. Regarding the areas, the north and center sites showed similar meteorological conditions and fungal community composition patterns. According to the Shannon and Simpson indices, the south area showed a greater species diversity during the dry season. These insights into the interactions between urbanization, seasonality, and airborne microbial communities could contribute to more effective urban management, reduced health risks, and the promotion of sustainable development. Full article

Fungi of the genus Aspergillus are widespread in the environment, where they produce large quantities of airborne conidia. Inhalation of Aspergillus spp. conidia in immunocompromised individuals can cause a wide spectrum of diseases, ranging from hypersensitivity responses to lethal invasive infections. Upon deposition in the lung epithelial surface, conidia encounter and interact with complex microbial communities that constitute the lung microbiota. The lung microbiota has been suggested to influence the establishment and growth of Aspergillus spp. in the human airways. However, the mechanisms underlying this interaction have not yet been sufficiently investigated. In this study, we aimed to enrich and isolate bacterial strains capable of inhibiting the germination and growth of A. fumigatus conidia from bronchoalveolar lavage fluid (BALF) samples of lung transplant recipients using a novel enrichment method. This method is based on a soft agar overlay plate assay in which bacteria are directly in contact with conidia, allowing inhibition to be readily observed during enrichment. We isolated a total of five clonal bacterial strains with identical genotypic fingerprints, as shown by random amplified polymorphic DNA PCR (RAPD–PCR). All strains were identified as Pseudomonas aeruginosa (strains b1–b5). The strains were able to inhibit the germination and growth of Aspergillus fumigatus in a soft agar confrontation assay, as well as in a germination multiplate assay. Moreover, when compared with ten P. aeruginosa strains isolated from expectoration through standard methods, no significant differences in inhibitory potential were observed. Additionally, we showed inhibition of A. fumigatus growth on Calu-3 cell culture monolayers. However, the isolated P. aeruginosa strains were shown to cause significant damage to the cell monolayers. Overall, although P. aeruginosa is a known opportunistic lung pathogen and antagonist of A. fumigatus, we validated this novel one-step enrichment approach for the isolation of bacterial strains antagonistic to A. fumigatus from BALF samples as a proof-of-concept. This opens up a new venue for the targeted enrichment of antagonistic bacterial strains against specific fungal pathogens. Full article

This study investigates airborne bacterial and fungal communities in south-eastern Italy and Albania using advanced DNA-based techniques and compositional data analysis (CoDa). We assess the significance of airborne microbial communities, detailing our methodologies for site selection, sample collection, DNA extraction, and data analysis. Our results reveal distinct differences in microbial composition between the two regions, driven by local environmental factors. Specifically, Albanian samples showed higher abundances of bacterial species such as Rubellimicrobium roseum and Sphingomonas cynarae, while Italian samples were characterized by a prevalence of Truepera radiovictrix and Rubrobacter radiotolerans. In terms of fungi, Albanian sites exhibited greater abundance of Mycosphaerella tassiana, Aureobasidium pullulans, and Ascochyta herbicola. Aitchison distance-based dendrograms and principal component analysis (PCA) biplots, utilizing singular value decomposition, clearly delineated a geographical separation of microbial communities, underscoring the impact of regional atmospheric conditions on microbial composition. In the discussion, we interpret these findings in the context of regional environmental factors, highlighting their implications for understanding regional differences in airborne microbial communities. The conclusion emphasizes the effectiveness of advanced DNA techniques and CoDa in environmental microbiology, offering insights into how local environmental conditions shape microbial communities and suggesting directions for future research and public health considerations. Full article

Fungi are an important part of the atmospheric ecosystem yet an underexplored group. Airborne pathogenic fungi are the root cause of hypersensitive and allergenic states highly prevalent in Kuwait. Frequent dust storms in the region carry them further into the urban areas, posing an occupational health hazard. The fungal population associated with the respirable (more than 2.5 µm) and inhalable (2.5 µm and less) fractions of aerosols is negligibly explored and warrants comprehensive profiling to pinpoint tAhe health implications. For the present investigation, aerosol was collected using a high-volume air sampler coupled with a six-stage cascade impactor (Tisch Environmental, Inc) at a rate of 566 L min⁻¹. The samples were lysed, DNA was extracted, and the internal transcribed regions were sequenced through targeted amplicon sequencing. Aspergillus, Penicillium, Alternaria, Cladosporium, Fusarium, Gleotinia and Cryptococcus were recorded in all the size fractions with mean relative abundances (RA%) of 17.5%, 12.9%, 12.9%, 4.85%, 4.08%, 2.77%, and 2.51%, respectively. A weak community structure was associated with each size fraction (ANOSIM r² = 0.11; p > 0.05). The Shannon and Simpson indices also varied among the respirable and inhalable aerosols. About 24 genera were significantly differentially abundant, as described through the Wilcoxon rank sum test (p < 0.05). The fungal microbiome existed as a complex lattice of networks exhibiting both positive and negative correlations and were involved in 428 functions. All the predominant genera were pathogenic, hence, their presence in inhalable fractions raises concerns and poses an occupational exposure risk to both human and non-human biota. Moreover, long-range transport of these fungi to urban locations is undesirable yet plausible. Full article

Fungi are ubiquitous and metabolically versatile. Their dispersion has important scientific, environmental, health, and economic implications. They can be dispersed through the air by the aerosolization of near surfaces or transported from distant sources. Here, we tested the contribution of local (scale of meters) versus regional (kilometers) sources by analyzing an airborne fungal community by ITS sequencing around a copper mine in the North of Chile. The mine was the regional source, whereas the soil and vegetal detritus were the local sources at each point. The airborne community was highly homogeneous at ca. 2000 km², impeding the detection of regional or local contributions. Ascomycota was the dominant phylum in the three communities. Soil and vegetal detritus communities had lower alpha diversity, but some taxa had abundance patterns related to the distance from the mine and altitude. On the contrary, the air was compositionally even and unrelated to environmental or spatial factors, except for altitude. The presence of plant pathogens in the air suggests that other distant sources contribute to this region’s airborne fungal community and reinforces the complexity of tracking the sources of air microbial communities in a real world where several natural and human activities coexist. Full article

To date, there have been no DNA-based metabarcoding studies into airborne fungi in tropical Sub-Saharan Africa. In this initial study, 10 air samples were collected onto Vaseline-coated acrylic rods mounted on drones flown at heights of 15–50 meters above ground for 10–15 min at three sites in Ghana. Purified DNA was extracted from air samples, the internal transcribed spacer (ITS) region was amplified using fungal-specific primers, and MinION third-generation amplicon sequencing was undertaken with downstream bioinformatics analyses utilizing GAIA cloud-based software (at genus taxonomic level). Principal coordinate analyses based on Bray–Curtis beta diversity dissimilarity values found no clear evidence for the structuring of fungal air communities, nor were there significant differences in alpha diversity, based on geographic location (east vs. central Ghana), underlying vegetation type (cocoa vs. non-cocoa), or height above ground level (15–23 m vs. 25–50 m), and despite the short flight times (10–15 min), ~90 operational taxonomic units (OTUs) were identified in each sample. In Ghanaian air, fungal assemblages were skewed at the phylum taxonomic level towards the ascomycetes (53.7%) as opposed to basidiomycetes (24.6%); at the class level, the Dothideomycetes were predominant (29.8%) followed by the Agaricomycetes (21.8%). The most common fungal genus in Ghanaian air was cosmopolitan and globally ubiquitous Cladosporium (9.9% of reads). Interestingly, many fungal genera containing economically important phytopathogens of tropical crops were also identified in Ghanaian air, including Corynespora, Fusarium, and Lasiodiplodia. Consequently, a novel loop-mediated isothermal amplification (LAMP) assay, based on translation elongation factor-1α sequences, was developed and tested for rapid, sensitive, and specific detection of the fungal phytopathogenic genus Lasiodiplodia. Potential applications for improved tropical disease management are considered. Full article

A study was carried out in a waste sorting plant (WSP) located in France, treating dry recyclable household waste (DRHW) as well as dry recyclable commercial and industrial waste (DRCIW). Stationary and personal inhalable samples were collected in the WSP in order to investigate bioaerosols (sampling on a filter; 2 L/min and 10 L/min) and airborne dust (CIP; 10 L/min). The aim of the study was to assess the extent to which the measurement of concentration, species composition, and particle size distribution contributes to a better assessment of the biological risks associated with exposure. The results confirmed that waste and waste sorting activities are sources of airborne fungi. Indeed, ambient concentrations ranged from 7.3 × 10³ to 8.5 × 10⁵ colony-forming units (CFU)/m³ for culturable fungi and up to 4 mg/m³ for dust. Personal exposure to inhalable dust was found up to 3 mg/m³ for dust and ranged from 8.6 × 10³ to 1.5 × 10⁶ CFU/m³ for fungi. Airborne fungal communities were found to be dominated by the Penicillium genera in both bioaerosols and settled dust samples, followed by the Aspergillus, Cladosporium, Wallemia, Mucor, and Rhizopus genera. Fungi were carried by particles of aerodynamic diameters, mainly between around 2.0 and 10.0 µm. The findings dealing with size distribution and biodiversity of bioaerosols suggest that employees are exposed to complex bioaerosols during their work and help to make a finer diagnosis of the risks involved, which is often difficult in the absence of any occupational exposure limit (OEL) value for bioaerosols in general. Full article

Airborne fungi play an important role in air pollution and may have various negative effects on human health. In particular, Aspergillus fungi are pathogenic to humans and several domestic animals. In this work, Aspergillus strains isolated from airborne fungal communities sampled from different indoor and outdoor environments in Tianjin University were tested for pathogenicity on Drosophila melanogaster. Airborne fungi were sampled using an HAS-100B air sampler, over a one-year sampling period. Isolated fungal strains were identified based on morphological and molecular analysis. The Aspergillus-centered study was conducted as part of a larger work focusing on the total airborne fungal community in the analyzed environments, which yielded 173 fungal species. In this context, the genus Aspergillus showed the second-highest species richness, with 14 isolated species. Pathogenicity tests performed on male adults of Drosophila melanogaster through a bodily contact bioassay showed that all analyzed airborne Aspergillus species were pathogenic to fruit flies, with high insect mortality rates and shortened lifespan. All the studied fungi induced 100% mortality of fruit flies within 30 culture days, with one exception constituted by A. creber (39 days), while the shortest lifespan (17 days) was observed in fruit flies treated with A. tubingensis. Our results allow us to hypothesize that the studied airborne fungal species may have a pathogenic effect on humans, given the affinity between fruit flies and the human immune system, and may help to explain the health risk linked with Aspergillus fungi exposure in densely populated environments. Full article

Airborne fungal spores constitute an important type of bioaerosol and are responsible for a number of negative effects on human health, including respiratory diseases and allergies. We investigated the diversity and concentration of culturable airborne fungi on pedestrian bridges in Tianjin, China, using an HAS-100B air sampler. We compared the airborne fungal communities at the top central area of the selected pedestrian bridges and along the corresponding sidewalk, at ground level. A total of 228 fungal strains belonging to 96 species and 58 genera of Ascomycota (68.86%), Basidiomycota (30.26%), and Mucoromycota (0.88%) were isolated and identified using morphological and molecular analysis. Alternaria was the dominant genus (20.61%), followed by Cladosporium (11.48%), Schizophyllum (6.14%), Sporobolomyces (5.70%), and Sporidiobolus (4.82%). Alternaria alternata was the most frequently occurring fungal species (6.58%), followed by Schizophyllum commune (5.26%), Alternaria sp. (4.82%), Sporobolomyces carnicolor (4.39%), and Cladosporium cladosporioides (3.95%). The recorded fungal concentration ranged from 10 to 180 CFU/m³. Although there was no significant difference in the distribution and abundance of the dominant airborne fungal taxa between the two investigated bridges’ sites, numerous species detected with a low percentage of abundance belonging to well-known pathogenic fungal genera, including Alternaria, Aspergillus, Aureobasidium, Cladosporium, Penicillium, and Trichoderma, were exclusively present in one of the two sites. The relative humidity showed a stronger influence compared to the temperature on the diversity and concentration of airborne fungi in the investigated sites. Our results may provide valuable information for air quality monitoring and for assessing human health risks associated with microbial pollution. Full article

Fine particulate matter (PM_2.5) can carry numerous substances and penetrate deep into the respiratory tract due to its small particle size; associated harmful microorganisms are suspected to increase health risks for humans and animals. To find out the microbial compositions of PM_2.5 in piggeries, their interaction and traceability, we collected PM_2.5 samples from a piggery while continuously monitoring the environmental indicators. We also identified pathogenic bacteria and allergens in the samples using high-throughput sequencing technology. We analyzed the microbial differences of PM_2.5 samples at different heights and during different times of day and investigated the microbial dynamics among the PM_2.5 samples. To better understand the interaction between microorganisms and environmental factors among different microbial communities, we applied the network analysis method to identify the correlation among various variables. Finally, SourceTracker, a commonly used microbial traceability tool, was used to predict the source of airborne microorganisms in the pig house. We identified 14 potential pathogenic bacteria and 5 allergens from PM_2.5 in the pig houses, of which Acinetobacter was the dominant bacterium in all samples (relative abundance > 1%), which warrants attention. We found that bacteria and fungi directly affected the the microbial community. The bacterial community mainly played a positive role in the microbial community. Environmental variables mainly indirectly and positively affected microbial abundance. In the SourceTracker analysis using fecal matter and feed as sources and PM_2.5 sample as sink, we found that fecal matter made the greatest contribution to both bacterial and fungal components of PM_2.5. Our findings provide important insights into the potential risks of pathogens in PM_2.5 to human and animal health and their main sources. Full article

It is now well established that biological pollution is a major cause of the degradation of indoor air quality. It has been shown that microbial communities from the outdoors may significantly impact the communities detected indoors. One can reasonably assume that the fungal contamination of the surfaces of building materials and their release into indoor air may also significantly impact indoor air quality. Fungi are well known as common contaminants of the indoor environment with the ability to grow on many types of building materials and to subsequently release biological particles into the indoor air. The aerosolization of allergenic compounds or mycotoxins borne by fungal particles or vehiculated by dust may have a direct impact on the occupant’s health. However, to date, very few studies have investigated such an impact. The present paper reviewed the available data on indoor fungal contamination in different types of buildings with the aim of highlighting the direct connections between the growth on indoor building materials and the degradation of indoor air quality through the aerosolization of mycotoxins. Some studies showed that average airborne fungal spore concentrations were higher in buildings where mould was a contaminant than in normal buildings and that there was a strong association between fungal contamination and health problems for occupants. In addition, the most frequent fungal species on surfaces are also those most commonly identified in indoor air, regardless the geographical location in Europe or the USA. Some fungal species contaminating the indoors may be dangerous for human health as they produce mycotoxins. These contaminants, when aerosolized with fungal particles, can be inhaled and may endanger human health. However, it appears that more work is needed to characterize the direct impact of surface contamination on the airborne fungal particle concentration. In addition, fungal species growing in buildings and their known mycotoxins are different from those contaminating foods. This is why further in situ studies to identify fungal contaminants at the species level and to quantify their average concentration on both surfaces and in the air are needed to be better predict health risks due to mycotoxin aerosolization. Full article

Sport facilities represent extreme indoor environments due to intense cleaning and disinfection. The aim of this study was to describe the composition of the cultivated microbiota in dust samples collected in sport facilities during the COVID-19 pandemic. A dust sample is defined as the airborne dust sedimented on 0.02 m² within 28 d. The results show that the microbial viable counts in samples of airborne dust (n = 9) collected from seven Finnish sport facilities during the pandemic contained a high proportion of pathogenic filamentous fungi and a low proportion of bacteria. The microbial viable counts were between 14 CFU and 189 CFU per dust sample. In seven samples from sport facilities, 20–85% of the microbial viable counts were fungi. Out of 123 fungal colonies, 47 colonies belonged to the potentially pathogenic sections of Aspergillus (Sections Fumigati, Nigri, and Flavi). Representatives of each section were identified as Aspergillus fumigatus, A. flavus, A. niger and A. tubingensis. Six colonies belonged to the genus Paecilomyces. In six samples of dust, a high proportion (50–100%) of the total fungal viable counts consisted of these potentially pathogenic fungi. A total of 70 isolates were considered less likely to be pathogenic, and were identified as Aspergillus section Nidulantes, Chaetomium cochliodes and Penicillium sp. In the rural (n = 2) and urban (n = 7) control dust samples, the microbial viable counts were >2000 CFU and between 44 CFU and 215 CFU, respectively, and consisted mainly of bacteria. The low proportion of bacteria and the high proportion of stress tolerant, potentially pathogenic fungi in the dust samples from sport facilities may reflect the influence of disinfection on microbial communities. Full article

Exposure to particular microbiome compositions in the built environment can affect human health and well-being. Identifying the drivers of these indoor microbial assemblages is key to controlling the microbiota of the built environment. In the present study, we used culture and metabarcoding of the fungal Internal Transcribed Spacer ribosomal RNA region to assess whether small-scale variation in the built environment influences the diversity, composition and structure of indoor air fungal communities between a heating and an unheated season. Passive dust collectors were used to collect airborne fungi from 259 dwellings representative of three major building periods and five building environments in one city—Lausanne (Vaud, Switzerland)—over a heating and an unheated period. A homogenous population (one or two people with an average age of 75 years) inhabited the households. Geographic information systems were used to assess detailed site characteristics (altitude, proximity to forest, fields and parks, proximity to the lake, and density of buildings and roads) for each building. Our analysis indicated that season was the factor that explained most of the variation in colonies forming unit (CFU) concentration and indoor mycobiome composition, followed by the period of building construction. Fungal assemblages were more diverse during the heating season than during the unheated season. Buildings with effective insulation had distinct mycobiome compositions from those built before 1975 — regardless of whether they were constructed with pre-1945 technology and materials or 1945 — 1974 ones. The urban landscape—as a whole—was a significant predictor of cultivable Penicillium load—the closer the building was to the lake, the higher the Penicillium load—but not of fungal community composition. Nevertheless, the relative abundance of eleven fungal taxa detected by metabarcoding decreased significantly with the urbanization gradient. When urban landscape descriptors were analyzed separately, the explanatory power of proximity to vegetation in shaping fungal assemblages become significant, indicating that land cover type had an influence on fungal community structure that was obscured by the effects of building age and sampling season. In conclusion, indoor mycobiomes are strongly modulated by season, and their assemblages are shaped by the effectiveness of building insulation, but are weakly influenced by the urban landscape. Full article