Detection of Indoor Fungi

A special issue of Pathogens (ISSN 2076-0817). This special issue belongs to the section "Fungal Pathogens".

Deadline for manuscript submissions: closed (31 July 2023) | Viewed by 39755

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National Center for Public Health and Pharmacy, Albert Flórián út 2-6, H-1097 Budapest, Hungary
Interests: aerobiology; fungal spore dispersal; fungal diversity
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Dear Colleagues,

Building dampness or mold has been shown to be associated quite consistently with a variety of adverse health effects according to reviews carried out on a long list of studies from different geographic areas by scientific bodies, including the WHO. The most relevant diseases that molds can cause are allergies, hypersensitivity pneumonitis, and infection. The prevalence of mold allergy is approximately 5% to 30% of patients with atopy. However, there are still many questions and uncertainties around other symptoms, as well as the severity of health risk represented by mold contamination. These precautions stem from many factors, e.g., the fact that the metabolism of fungi (production of mycotoxins, MVOCs, and antigens) depends on many factors; that standardized fungal extracts are not available for clinical studies; and that questionnaire-based studies assessing dampness or mold most often rely on answers from the building occupants which may underestimate the real level of fungal contamination. Finally, common mold detection methods seem to be insufficient (e.g., low volume and frequency of air samples). Detection of indoor mold growth is challenging, even for trained people, and modern architecture does not make the situation any easier, as building materials widely used in modern buildings (e.g., drywall, dropped ceiling, fibrous insulation materials), once wetted, offer an appropriate environment for fungal growth, which often remains unobserved by residents or even professionals.

There are many points of view from which mold problems can be discussed; our focus will be on the detection of fungi in the indoor environment. For this Special Issue of the journal Pathogens, we invite you to submit innovative research papers and review articles as well as brief communications presenting recent advances related to our knowledge of fungi in enclosed spaces, including homes, office buildings, schools, healthcare and industrial settings and extreme indoor environments (HVAC, household devices), etc. Research papers and reviews can cover any aspect of detection methods and related issues of biodiversity, substrate preference, interaction with modern building materials, (chemo)taxonomic and phylogenetic studies, metabolism, pathogenicity, and strategies for mold remediation. We look forward to your contribution.

Dr. Donát Magyar
Guest Editor

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Keywords

  • molds
  • fungi
  • indoor environment
  • indoor air quality and molds
  • mycotoxins
  • fungal MVOCs
  • fungal allergens
  • pathogenic fungi in the indoor environment
  • biodeterioration by fungi in the indoor environment
  • aeromycology
  • fungal diversity

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Published Papers (13 papers)

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Editorial

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4 pages, 220 KiB  
Editorial
Recent Advances in the Detection of Indoor Fungi
by Donát Magyar
Pathogens 2023, 12(9), 1136; https://doi.org/10.3390/pathogens12091136 - 6 Sep 2023
Cited by 1 | Viewed by 1089
Abstract
According to reviews carried out by numerous studies from different geographic areas and by several scientific bodies, including the WHO [...] Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)

Research

Jump to: Editorial, Review

18 pages, 10869 KiB  
Article
Indoor Bacterial and Fungal Burden in “Moldy” versus “Non-Moldy” Homes: A Case Study Employing Advanced Sequencing Techniques in a US Metropolitan Area
by Bhavin V. Chauhan, Daleniece Higgins Jones, Goutam Banerjee, Saumya Agrawal, Irshad M. Sulaiman, Chunrong Jia and Pratik Banerjee
Pathogens 2023, 12(8), 1006; https://doi.org/10.3390/pathogens12081006 - 1 Aug 2023
Cited by 3 | Viewed by 2091
Abstract
The presence of fungi in the indoor environment is associated with allergies and other respiratory symptoms. The aim of this study was to use sequencing and molecular methods, including next-generation sequencing (NGS) approaches, to explore the bacterial and fungal communities and their abundance [...] Read more.
The presence of fungi in the indoor environment is associated with allergies and other respiratory symptoms. The aim of this study was to use sequencing and molecular methods, including next-generation sequencing (NGS) approaches, to explore the bacterial and fungal communities and their abundance in the indoor environment of houses (n = 20) with visible “moldy” (HVM) and nonvisible “non-moldy” (HNM) in Memphis, TN, USA. Dust samples were collected from air vents and ground surfaces, and the total DNA was analyzed for bacteria and fungi by amplifying 16S rRNA and ITS genes on the Illumina Miseq. Results indicated that Leptosphaerulina was the most abundant fungal genus present in the air vent and ground samples from HNM and HVM. At the same time, the most abundant bacterial genera in the air vent and ground samples were Propionibacterium and Streptococcus. The fungi community diversity was significantly different in the air vent samples. The abundance of fungal species known to be associated with respiratory diseases in indoor dust samples was similar, regardless of the visibility of fungi in the houses. The existence of fungi associated with respiratory symptoms was compared with several parameters like dust particulate matter (PM), CO2 level, temperature, and humidity. Most of these parameters are either positively or negatively correlated with the existence of fungi associated with respiratory diseases; however, none of these correlations were significant at p = 0.05. Our results indicate that implementing molecular methods for detecting indoor fungi may strengthen common exposure and risk assessment practices. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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16 pages, 1624 KiB  
Article
Combined Toxicity of the Most Common Indoor Aspergilli
by Daniela Jakšić, Dubravko Jelić, Nevenka Kopjar and Maja Šegvić Klarić
Pathogens 2023, 12(3), 459; https://doi.org/10.3390/pathogens12030459 - 14 Mar 2023
Cited by 1 | Viewed by 2154
Abstract
The most common Aspergilli isolated from indoor air samples from occupied buildings and a grain mill were extracted and analyzed for their combined (Flavi + Nigri, Versicolores + Nigri) cytotoxic, genotoxic and pro-inflammatory properties on human adenocarcinoma cells (A549) and [...] Read more.
The most common Aspergilli isolated from indoor air samples from occupied buildings and a grain mill were extracted and analyzed for their combined (Flavi + Nigri, Versicolores + Nigri) cytotoxic, genotoxic and pro-inflammatory properties on human adenocarcinoma cells (A549) and monocytic leukemia cells induced in macrophages (THP-1 macrophages). Metabolite mixtures from the Aspergilli series Nigri increase the cytotoxic and genotoxic potency of Flavi extracts in A549 cells suggesting additive and/or synergistic effects, while antagonizing the cytotoxic potency of Versicolores extracts in THP-1 macrophages and genotoxicity in A549 cells. All tested combinations significantly decreased IL-5 and IL-17, while IL-1β, TNF-α and IL-6 relative concentrations were increased. Exploring the toxicity of extracted Aspergilli deepens the understanding of intersections and interspecies differences in events of chronic exposure to their inhalable mycoparticles. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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16 pages, 2846 KiB  
Article
Composition of Culturable Microorganisms in Dusts Collected from Sport Facilities in Finland during the COVID-19 Pandemic
by Maria (Aino) Andersson, Camilla Vornanen-Winqvist, Tuomas Koivisto, András Varga, Raimo Mikkola, László Kredics and Heidi Salonen
Pathogens 2023, 12(2), 339; https://doi.org/10.3390/pathogens12020339 - 16 Feb 2023
Cited by 2 | Viewed by 3165
Abstract
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 [...] Read more.
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
(This article belongs to the Special Issue Detection of Indoor Fungi)
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20 pages, 2559 KiB  
Article
Biomonitoring of Indoor Air Fungal or Chemical Toxins with Caenorhabditis elegans nematodes
by Sari Paavanen-Huhtala, Karunambigai Kalichamy, Anna-Mari Pessi, Sirkku Häkkilä, Annika Saarto, Marja Tuomela, Maria A. Andersson and Päivi J. Koskinen
Pathogens 2023, 12(2), 161; https://doi.org/10.3390/pathogens12020161 - 19 Jan 2023
Cited by 2 | Viewed by 3680
Abstract
Bad indoor air quality due to toxins and other impurities can have a negative impact on human well-being, working capacity and health. Therefore, reliable methods to monitor the health risks associated with exposure to hazardous indoor air agents are needed. Here, we have [...] Read more.
Bad indoor air quality due to toxins and other impurities can have a negative impact on human well-being, working capacity and health. Therefore, reliable methods to monitor the health risks associated with exposure to hazardous indoor air agents are needed. Here, we have used transgenic Caenorhabditis elegans nematode strains carrying stress-responsive fluorescent reporters and evaluated their ability to sense fungal or chemical toxins, especially those that are present in moisture-damaged buildings. Liquid-based or airborne exposure of nematodes to mycotoxins, chemical agents or damaged building materials reproducibly resulted in time- and dose-dependent fluorescent responses, which could be quantitated by either microscopy or spectrometry. Thus, the C. elegans nematodes present an easy, ethically acceptable and comprehensive in vivo model system to monitor the response of multicellular organisms to indoor air toxicity. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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19 pages, 4845 KiB  
Article
Biophysical Manipulation of the Extracellular Environment by Eurotium halophilicum
by Anna Micheluz, Flavia Pinzari, Edgard G. Rivera-Valentín, Sabrina Manente and John E. Hallsworth
Pathogens 2022, 11(12), 1462; https://doi.org/10.3390/pathogens11121462 - 2 Dec 2022
Cited by 11 | Viewed by 2170
Abstract
Eurotium halophilicum is psychrotolerant, halophilic, and one of the most-extreme xerophiles in Earth’s biosphere. We already know that this ascomycete grows close to 0 °C, at high NaCl, and—under some conditions—down to 0.651 water-activity. However, there is a paucity of information about how [...] Read more.
Eurotium halophilicum is psychrotolerant, halophilic, and one of the most-extreme xerophiles in Earth’s biosphere. We already know that this ascomycete grows close to 0 °C, at high NaCl, and—under some conditions—down to 0.651 water-activity. However, there is a paucity of information about how it achieves this extreme stress tolerance given the dynamic water regimes of the surface habitats on which it commonly occurs. Here, against the backdrop of global climate change, we investigated the biophysical interactions of E. halophilicum with its extracellular environment using samples taken from the surfaces of library books. The specific aims were to examine its morphology and extracellular environment (using scanning electron microscopy for visualisation and energy-dispersive X-ray spectrometry to identify chemical elements) and investigate interactions with water, ions, and minerals (including analyses of temperature and relative humidity conditions and determinations of salt deliquescence and water activity of extracellular brine). We observed crystals identified as eugsterite (Na4Ca(SO4)3·2H2O) and mirabilite (Na2SO4·10H2O) embedded within extracellular polymeric substances and provide evidence that E. halophilicum uses salt deliquescence to maintain conditions consistent with its water-activity window for growth. In addition, it utilizes a covering of hair-like microfilaments that likely absorb water and maintain a layer of humid air adjacent to the hyphae. We believe that, along with compatible solutes used for osmotic adjustment, these adaptations allow the fungus to maintain hydration in both space and time. We discuss these findings in relation to the conservation of books and other artifacts within the built environment, spoilage of foods and feeds, the ecology of E. halophilicum in natural habitats, and the current episode of climate change. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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22 pages, 20303 KiB  
Article
Aspergillus Was the Dominant Genus Found during Diversity Tracking of Potentially Pathogenic Indoor Fungal Isolates
by Maria Andersson (Aino), András Varga, Raimo Mikkola, Camilla Vornanen-Winqvist, Johanna Salo, László Kredics, Sándor Kocsubé and Heidi Salonen
Pathogens 2022, 11(10), 1171; https://doi.org/10.3390/pathogens11101171 - 11 Oct 2022
Cited by 6 | Viewed by 2745
Abstract
Viable airborne pathogenic fungi represent a potential health hazard when exposing vulnerable persons in quantities exceeding their resilience. In this study, 284 indoor fungal isolates from a strain collection of indoor fungi were screened for pathogenic potential through the ability to grow in [...] Read more.
Viable airborne pathogenic fungi represent a potential health hazard when exposing vulnerable persons in quantities exceeding their resilience. In this study, 284 indoor fungal isolates from a strain collection of indoor fungi were screened for pathogenic potential through the ability to grow in neutral pH at 37 °C and 30 °C. The isolates were collected from 20 locations including 14 problematic and 6 non-problematic ordinary buildings. Out of the screened isolates, 170 isolates were unable to grow at 37 °C, whereas 67 isolates growing at pH 7.2 at 37 °C were considered as potential opportunistic pathogens. Forty-seven isolates growing at 30 °C but not at 37 °C were considered as less likely pathogens. Out of these categories, 33 and 33 strains, respectively, were identified to the species level. The problematic buildings included known opportunistic pathogens: Aspergillus calidoustus, Trichoderma longibrachiatum, Rhizopus arrhizus and Paecilomyces variotii, as well as less likely pathogens: Aspergillus versicolor, Chaetomium cochliodes, Chaetomium globosum and Chaetomium rectangulare. Opportunistic pathogens such as Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger and Aspergillus tubingensis and less likely pathogens such as Aspergillus westerdijkiae, Chaetomium globosum and Dichotomopilus finlandicus were isolated both from ordinary and from problematic buildings. Aspergillus was the dominant, most diverse genus found during screening for potentially pathogenic isolates in the indoor strain collection. Studies on Aspergillus niger and Aspergillus calidodoustus revealed that tolerance to cleaning chemicals may contribute to the adaptation of Aspergillus species to indoor environments. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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14 pages, 2586 KiB  
Article
Hagnosa longicapillata, gen. nov., sp. nov., a New Sordariaceous Ascomycete in the Indoor Environment, and the Proposal of Hagnosaceae fam. nov.
by Donát Magyar, András Tartally and Zsolt Merényi
Pathogens 2022, 11(5), 593; https://doi.org/10.3390/pathogens11050593 - 18 May 2022
Cited by 3 | Viewed by 2634
Abstract
Hagnosa longicapillata, gen. nov., sp. nov, is described and illustrated from wooden building materials collected in Hungary and from pure culture. This species has been collected exclusively from indoor environments, where it was quite common. The ascocarps develop in a thick layer [...] Read more.
Hagnosa longicapillata, gen. nov., sp. nov, is described and illustrated from wooden building materials collected in Hungary and from pure culture. This species has been collected exclusively from indoor environments, where it was quite common. The ascocarps develop in a thick layer of brown, woolly mats of mycelia. The ostiolar region of the perithecia is ornamented with a five-lobed, flower-shaped crown. Asci are four-spored; ascospores are dark brown, smooth, muriform, not constricted at the septa, and liberated mostly through crackings of the thin ascomatal wall. Apparently, ascospores are dispersed by the mechanical disturbance of the mycelial web. In the phylogenetic tree, Hagnosa samples were placed as a basal lineage, independently from the other family of Sordariomycetidae, with high support. To place Hagnosa in Sordariales, the new family, Hagnosaceae, is proposed. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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18 pages, 1567 KiB  
Article
The Toxicity of Wiped Dust and Airborne Microbes in Individual Classrooms Increase the Risk of Teachers’ Work-Related Symptoms: A Cross-Sectional Study
by Janne Salin, Pasi Ohtonen, Maria A. Andersson and Hannu Syrjälä
Pathogens 2021, 10(11), 1360; https://doi.org/10.3390/pathogens10111360 - 21 Oct 2021
Cited by 8 | Viewed by 2782
Abstract
Background: The causes and pathophysiological mechanisms of building-related symptoms (BRS) remain open. Objective: We aimed to investigate the association between teachers’ individual work-related symptoms and intrinsic in vitro toxicity in classrooms. This is a further analysis of a previously published dataset. Methods: Teachers [...] Read more.
Background: The causes and pathophysiological mechanisms of building-related symptoms (BRS) remain open. Objective: We aimed to investigate the association between teachers’ individual work-related symptoms and intrinsic in vitro toxicity in classrooms. This is a further analysis of a previously published dataset. Methods: Teachers from 15 Finnish schools in Helsinki responded to the symptom survey. The boar sperm motility inhibition assay, a sensitive indicator of mitochondrial dysfunction, was used to measure the toxicity of wiped dust and cultured microbial fallout samples collected from the teachers’ classrooms. Results: 231 teachers whose classroom toxicity data had been collected responded to the questionnaire. Logistic regression analysis adjusted for age, gender, smoking, and atopy showed that classroom dust intrinsic toxicity was statistically significantly associated with the following 12 symptoms reported by teachers (adjusted ORs in parentheses): nose stuffiness (4.1), runny nose (6.9), hoarseness (6.4), globus sensation (9.0), throat mucus (7.6), throat itching (4.4), shortness of breath (12.2), dry cough (4.7), wet eyes (12.7), hypersensitivity to sound (7.9), difficulty falling asleep (7.6), and increased need for sleep (7.7). Toxicity of cultured microbes was found to be associated with nine symptoms (adjusted ORs in parentheses): headache (2.3), nose stuffiness (2.2), nose dryness (2.2), mouth dryness (2.8), hoarseness (2.2), sore throat (2.8), throat mucus (2.3), eye discharge (10.2), and increased need for sleep (3.5). Conclusions: The toxicity of classroom dust and airborne microbes in boar sperm motility inhibition assay significantly increased teachers’ risk of work-related respiratory and ocular symptoms. Potential pathophysiological mechanisms of BRS are discussed. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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19 pages, 8691 KiB  
Article
Chaetomium and Chaetomium-like Species from European Indoor Environments Include Dichotomopilus finlandicus sp. nov.
by Orsolya Kedves, Sándor Kocsubé, Teodóra Bata, Maria A. Andersson, Johanna M. Salo, Raimo Mikkola, Heidi Salonen, Attila Szűcs, Alfonz Kedves, Zoltán Kónya, Csaba Vágvölgyi, Donát Magyar and László Kredics
Pathogens 2021, 10(9), 1133; https://doi.org/10.3390/pathogens10091133 - 3 Sep 2021
Cited by 12 | Viewed by 5575
Abstract
The genus Chaetomium is a frequently occurring fungal taxon world-wide. Chaetomium and Chaetomium-like species occur in indoor environments, where they can degrade cellulose-based building materials, thereby causing structural damage. Furthermore, several species of this genus may also cause adverse effects on human [...] Read more.
The genus Chaetomium is a frequently occurring fungal taxon world-wide. Chaetomium and Chaetomium-like species occur in indoor environments, where they can degrade cellulose-based building materials, thereby causing structural damage. Furthermore, several species of this genus may also cause adverse effects on human health. The aims of this research were to identify Chaetomium and Chaetomium-like strains isolated from indoor environments in Hungary and Finland, two geographically distant regions of Europe with drier and wetter continental climates, respectively, and to study their morphological and physiological properties, as well as their extracellular enzyme activities, thereby comparing the Chaetomium and Chaetomium-like species isolated from these two different regions of Europe and their properties. Chaetomium and Chaetomium-like strains were isolated from flats and offices in Hungary, as well as from schools, flats, and offices in Finland. Fragments of the translation elongation factor 1α (tef1α), the second largest subunit of RNA polymerase II (rpb2) and β-tubulin (tub2) genes, as well as the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster were sequenced, and phylogenetic analysis of the sequences performed. Morphological examinations were performed by stereomicroscopy and scanning electron microscopy. Thirty-one Chaetomium sp. strains (15 from Hungary and 16 from Finland) were examined during the study. The most abundant species was Ch. globosum in both countries. In Hungary, 13 strains were identified as Ch. globosum, 1 as Ch. cochliodes, and 1 as Ch. interruptum. In Finland, 10 strains were Ch. globosum, 2 strains were Ch. cochliodes, 2 were Ch. rectangulare, and 2 isolates (SZMC 26527, SZMC 26529) proved to be representatives of a yet undescribed phylogenetic species from the closely related genus Dichotomopilus, which we formally describe here as the new species Dichotomopilus finlandicus. Growth of the isolates was examined at different temperatures (4, 15, 20, 25, 30, 37, 35, 40, and 45 °C), while their extracellular enzyme production was determined spectrophotometrically. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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16 pages, 2456 KiB  
Article
Contribution of Visible Surface Mold to Airborne Fungal Concentration as Assessed by Digital Image Quantification
by Chun-Chieh Tseng, Ning Huang, Chia-Jung Hsieh, Chien-Che Hung and Yue-Liang Leon Guo
Pathogens 2021, 10(8), 1032; https://doi.org/10.3390/pathogens10081032 - 15 Aug 2021
Cited by 8 | Viewed by 2782
Abstract
The rapid monitoring of total fungi, including air and surface fungal profiling, is an important issue. Here, we applied air and surface sampling, combined with digital image quantification of surface mold spots, to evaluate the contribution of surface fungi to airborne fungal concentrations. [...] Read more.
The rapid monitoring of total fungi, including air and surface fungal profiling, is an important issue. Here, we applied air and surface sampling, combined with digital image quantification of surface mold spots, to evaluate the contribution of surface fungi to airborne fungal concentrations. Cladosporium, Penicillium, Aspergillus, and yeast often appeared in the air or on wall surfaces during sampling. The indoor/outdoor concentration ratios (I/O ratios) demonstrated that the airborne concentrations of commonly found fungal genera outdoors were higher than those indoors (median I/O ratio = 0.65–0.91), excluding those of Penicillium and yeast. Additionally, the surface density (fungal concentration/area) of individual fungi showed no significant correlation with the airborne concentration, excluding that of Geotrichum. However, if a higher surface ratio (>0.00031) of mold spots appeared in the total area of an indoor environment, then the concentrations of Aspergillus and Geotrichum in the air increased significantly. Our results demonstrated that the airborne concentration of indoor fungi is significantly correlated with the outdoor concentration. A higher density of surface fungi does not necessarily contribute to a high fungal concentration in the air. In contrast to fungal density, quantification of the surface fungal area is recommended to assess the risk of surface fungi propelling into the air. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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24 pages, 26657 KiB  
Article
Melinacidin-Producing Acrostalagmus luteoalbus, a Major Constituent of Mixed Mycobiota Contaminating Insulation Material in an Outdoor Wall
by (Aino) Maria A. Andersson, Johanna Salo, Raimo Mikkola, Tamás Marik, László Kredics, Jarek Kurnitski and Heidi Salonen
Pathogens 2021, 10(7), 843; https://doi.org/10.3390/pathogens10070843 - 4 Jul 2021
Cited by 8 | Viewed by 4581
Abstract
Occupants may complain about indoor air quality in closed spaces where the officially approved standard methods for indoor air quality risk assessment fail to reveal the cause of the problem. This study describes a rare genus not previously detected in Finnish buildings, Acrostalagmus [...] Read more.
Occupants may complain about indoor air quality in closed spaces where the officially approved standard methods for indoor air quality risk assessment fail to reveal the cause of the problem. This study describes a rare genus not previously detected in Finnish buildings, Acrostalagmus, and its species A. luteoalbus as the major constituents of the mixed microbiota in the wet cork liner from an outdoor wall. Representatives of the genus were also present in the settled dust in offices where occupants suffered from symptoms related to the indoor air. One strain, POB8, was identified as A. luteoalbus by ITS sequencing. The strain produced the immunosuppressive and cytotoxic melinacidins II, III, and IV, as evidenced by mass spectrometry analysis. In addition, the classical toxigenic species indicating water damage, mycoparasitic Trichoderma, Aspergillus section Versicolores, Aspergillus section Circumdati, Aspergillus section Nigri, and Chaetomium spp., were detected in the wet outdoor wall and settled dust from the problematic rooms. The offices exhibited no visible signs of microbial growth, and the airborne load of microbial conidia was too low to explain the reported symptoms. In conclusion, we suggest the possible migration of microbial bioactive metabolites from the wet outdoor wall into indoor spaces as a plausible explanation for the reported complaints. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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Review

Jump to: Editorial, Research

12 pages, 263 KiB  
Review
Electrostatic Dust Cloth: A Useful Passive Sampling Method When Assessing Exposure to Fungi Demonstrated in Studies Developed in Portugal (2018–2021)
by Carla Viegas, Marta Dias and Susana Viegas
Pathogens 2022, 11(3), 345; https://doi.org/10.3390/pathogens11030345 - 12 Mar 2022
Cited by 7 | Viewed by 2396
Abstract
Electrostatic dust cloths (EDC) have been widely used for microbiologic contamination assessment in different indoor and occupational environments. This paper reviews sixteen studies performed in Portugal between 2018 and 2021 for evaluating the exposure to microbiological agents and focusing on fungi using EDC [...] Read more.
Electrostatic dust cloths (EDC) have been widely used for microbiologic contamination assessment in different indoor and occupational environments. This paper reviews sixteen studies performed in Portugal between 2018 and 2021 for evaluating the exposure to microbiological agents and focusing on fungi using EDC as a passive sampling method. The findings suggest that EDC can be applied as a screening method for particulate matter-exposure assessment and as a complementary method to characterize microbial exposures in occupational environments. Overall, EDC should be included, side by side with other sampling methods, in sampling campaigns focused on exposure assessments due to the advantages such as the straightforward extraction protocol favoring the employment of different assays, which allows us to assess exposure to a wide range of microbial agents, and presents higher accuracy regarding the fungal diversity. Full article
(This article belongs to the Special Issue Detection of Indoor Fungi)
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