The roles of Penicillium and Aspergillus in sick building syndrome

Intermittent low-dose far-UVC irradiation inhibits growth of common mold below threshold limit value

Mold infestations in buildings pose significant challenges to human health, affecting both private residences and hospitals. While molds commonly trigger asthma and allergies in the immunocompetent, they can cause life-threatening diseases in the immunocompromised. Currently, there is an unmet need for new strategies to reduce or prevent mold infestations. Far-UVC technology can inactivate microorganisms while remaining safe for humans. This study investigates the inhibitory efficacy of far-UVC light at 222 nm on the growth of common mold-producing fungi, specifically Penicillium candidum, when delivered in low-dose on-off duty cycles, a configuration consistent with its use in real-world settings. The inhibitory effect of the low-dose duty cycles was assessed on growth induced by i) an adjacent spore-producing P. candidum donor and ii) P. candidum spores seeded directly onto agar plates. In both setups, the far-UVC light significantly inhibited both vertical and horizontal growth of P. candidum, even when the UV doses were below the Threshold Value Limit of 23 mJ/cm2. These results suggest that far-UVC light holds the potential to improve indoor air quality by reducing or preventing mold growth, also when people are present.

Taxonomy of Aspergillus series Versicolores: species reduction and lessons learned about intraspecific variability

Aspergillus series Versicolores members occur in a wide range of environments and substrates such as indoor environments, food, clinical materials, soil, caves, marine or hypersaline ecosystems. The taxonomy of the series has undergone numerous re-arrangements including a drastic reduction in the number of species and subsequent recovery to 17 species in the last decade. The identification to species level is however problematic or impossible in some isolates even using DNA sequencing or MALDI-TOF mass spectrometry indicating a problem in the definition of species boundaries. To revise the species limits, we assembled a large dataset of 518 strains. From these, a total of 213 strains were selected for the final analysis according to their calmodulin (CaM) genotype, substrate and geography. This set was used for phylogenetic analysis based on five loci (benA, CaM, RPB2, Mcm7, Tsr1). Apart from the classical phylogenetic methods, we used multispecies coalescence (MSC) model-based methods, including one multilocus method (STACEY) and five single-locus methods (GMYC, bGMYC, PTP, bPTP, ABGD). Almost all species delimitation methods suggested a broad species concept with only four species consistently supported. We also demonstrated that the currently applied concept of species is not sustainable as there are incongruences between single-gene phylogenies resulting in different species identifications when using different gene regions. Morphological and physiological data showed overall lack of good, taxonomically informative characters, which could be used for identification of such a large number of existing species. The characters expressed either low variability across species or significant intraspecific variability exceeding interspecific variability. Based on the above-mentioned results, we reduce series Versicolores to four species, namely A. versicolor, A. creber, A. sydowii and A. subversicolor, and the remaining species are synonymized with either A. versicolor or A. creber. The revised descriptions of the four accepted species are provided. They can all be identified by any of the five genes used in this study. Despite the large reduction in species number, identification based on phenotypic characters remains challenging, because the variation in phenotypic characters is high and overlapping among species, especially between A. versicolor and A. creber. Similar to the 17 narrowly defined species, the four broadly defined species do not have a specific ecology and are distributed worldwide. We expect that the application of comparable methodology with extensive sampling could lead to a similar reduction in the number of cryptic species in other extensively studied Aspergillus species complexes and other fungal genera. Citation: Sklenář F, Glässnerová K, Jurjević Ž, Houbraken J, Samson RA, Visagie CM, Yilmaz N, Gené J, Cano J, Chen AJ, Nováková A, Yaguchi T, Kolařík M, Hubka V (2022). Taxonomy of Aspergillus series Versicolores: species reduction and lessons learned about intraspecific variability. Studies in Mycology 102 : 53-93. doi: 10.3114/sim.2022.102.02.

Microbiological contamination of indoor and outdoor environments in a desert climate

Microbiological air contamination in the desert environment is becoming an essential subject for the health of office building occupants and public health. In this study, the concentrations and compositions of airborne microorganisms (bacteria and fungi) were assessed in indoor and outdoor environments using a multistory building complex in Kuwait as a case study. Airborne microorganism samples were collected from 12 sites within the building complex containing nineteen stories over four seasons. Culturable airborne bacteria and fungi were impacted on selected media to determine their concentrations and compositions with a Biolog Omnilog GEN III system and Biolog MicroStation. The indoor mean airborne bacterial count concentrations ranged from 35 to 18,463 CFU/m³, concentrations that are higher than 2,000 CFU/m³, demonstrating high-very high contamination levels in all seasons. Fungal contamination was high in winter and summer, with detected concentrations > 2,000 CFU/m³. Indoor-to-outdoor (I/O) ratios showed that airborne microbial contamination inside building floors originated from indoor air contamination. All the building floors showed bacterial and fungal concentrations ranging from less than 2,000 to more than 2,000 CFU/m³, indicative of a high to very high air contamination level. Statistical analysis showed no correlation between bacterial and fungal concentrations, demonstrating that they originated from unrelated sources. In the indoor building air, the most prevalent bacterial isolate was Bacillus pseudomycoides/cereus, whereas the most dominant fungal isolate was Aspergillus spp. The low count for indoor air bacterial species suggested no particular health risk for the occupants. In contrast, the high count of indoor air fungal species in the winter samples and the presence of potentially allergenic genera detected may suggest possible health risks for the occupants. The results obtained are the basis for the recommendation that the maintenance activities of the HVAC system and the periodical cleaning operation program be revised and preplanned as protective measures.

Greater Mouse-Eared Bats (Myotis myotis) Hibernating in the Nietoperek Bat Reserve (Poland) as a Vector of Airborne Culturable Fungi

Bats can contribute to an increase of aeromycota in underground ecosystems and might be a vector/reservoir of microorganisms; however, there is no information about the number and species composition of fungi around hibernating bats. One of the most common species in Europe with direct human contact is the greater mouse-eared bat (Myotis myotis). The goal of our research was the first report of the airborne fungi present in the close vicinity of hibernating M. myotis in the Nietoperek bat reserve (Western Poland) by the use of culture-based techniques and genetic and phenotypic identifications. Aerobiological investigations of mycobiota under hibernating bats were performed on two culture media (PDA and YPG) and at two incubation temperatures (7 and 24 ± 0.5 °C). Overall, we detected 32 fungal species from three phyla (Ascomycota, Basidiomycota, and Zygomycota) and 12 genera. The application of YPG medium and the higher incubation temperature showed higher numbers of isolated fungal species and CFU. Penicillium spp. were dominant in the study, with spores found outside the underground hibernation site from 51.9% to 86.3% and from 56.7% to 100% inside the bat reserve. Penicillium chrysogenum was the most frequently isolated species, then Absidia glauca, Aspergillus fumigatus, A. tubingensis, Mortierella polycephala, Naganishia diffluens, and Rhodotorula mucilaginosa. Temperature, relative humidity, and the abundance of bats correlated positively with the concentration of airborne fungal propagules, between fungal species diversity, and the concentration of aeromycota, but the number of fungal species did not positively correlate with the number of bats. The air in the underground site was more contaminated by fungi than the air outside; however, the concentration of aeromycota does not pose a threat for human health. Nevertheless, hibernating bats contribute to an increase in the aeromycota and as a vector/reservoir of microscopic fungi, including those that may cause allergies and infections in mammals, and should be monitored.

First Speleomycological Study on the Occurrence of Psychrophilic and Psychrotolerant Aeromycota in the Brestovská Cave (Western Tatras Mts., Slovakia) and First Reports for Some Species at Underground Sites

Most underground ecosystems are heterotrophic, fungi in these objects are dispersed in the air in the form of spores, and they may be potentially hazardous to mammals. Research in underground sites has focused on mesophilic airborne fungi and only a few concerned cold-adapted species. Therefore, the goal of our research was the first report of psychrophilic and psychrotolerant aeromycota in the Brestovská Cave using culture-based techniques with genetic and phenotypic identification. Plates with PDA medium containing sampled biological material were incubated at 8 ± 0.5 °C. The density of mycobiota inside the cave ranged from 37.4 to 71 CFU 1 m-3 of air and 63.3 CFU 1 m-3 of air outside the cave. Thus, the level of fungal spores did not exceed the standards for the mycological quality of the air. A total of 18 species were isolated during the study, and some species may be potentially dangerous to people with weakened immune system. All fungal species were present inside the cave and only seven of them were outside. Cladosporium cladosporioides dominated in the external air samples and Mortierella parvispora was cultured most frequently from internal air samples. To our knowledge, this is the first discovery of the fungal species such as Coniothyrium pyrinum, Cystobasidium laryngis, Filobasidium wieringae, Leucosporidium drummii, M. parvispora, Mrakia blollopis, Nakazawaea holstii, and Vishniacozyma victoriae in the air inside the underground sites. Moreover, C. pyrinum, C. laryngis, L. drummii, M. blollopis, and N. holstii have never been detected in any component of the underground ecosystems. There are possible reasons explaining the detection of those species, but global warming is the most likely.

Association between indoor microbiome exposure and sick building syndrome (SBS) in junior high schools of Johor Bahru, Malaysia

Sick building syndrome (SBS) is a collection of nonspecific syndromes linked with the built environment. The occurrence of SBS is associated with humidity, ventilation, moulds and microbial compounds exposure. However, no study has reported the association between indoor microbiome and SBS. In this study, 308 students were surveyed for SBS symptoms from 21 classrooms of 7 junior high schools from Johor Bahru, Malaysia, and vacuum dust from floor, desks and chairs was collected. High throughput amplicon sequencing (16S rRNA gene and ITS region) and quantitative PCR were conducted to characterize the absolute concentration of bacteria and fungi taxa. In total, 326 bacterial and 255 fungal genera were detected in dust with large compositional variation among classrooms. Also, half of these samples showed low compositional similarity to microbiome data deposited in the public database. The number of observed OTUs in Gammaproteobacteria was positively associated with SBS (p = 0.004). Eight microbial genera were associated with SBS (p < 0.01). Bacterial genera, Rhodomicrobium, Scytonema and Microcoleus, were protectively (negatively) associated with ocular and throat symptoms and tiredness, and Izhakiella and an unclassified genus from Euzebyaceae were positively associated with the throat and ocular symptoms. Three fungal genera, Polychaeton, Gympopus and an unclassified genus from Microbotryaceae, were mainly positively associated with tiredness. The associations differed with our previous study in microbial compounds (endotoxin and ergosterol) and SBS in the same population, in which nasal and dermal symptoms were affected. A higher indoor relative humidity and visible dampness or mould in classrooms were associated with a higher concentration of potential risk bacteria and a lower concentration of potential protective bacteria (p < 0.01). This is the first study to characterize the SBS-associated microorganisms in the indoor environment, revealing complex interactions between microbiome, SBS symptoms and environmental characteristics.

Volatile Organic Compounds Produced by Human Pathogenic Fungi Are Toxic to Drosophila melanogaster

Volatile organic compounds (VOCs) are low molecular mass organic compounds that easily evaporate at room temperature. Fungi produce diverse mixtures of VOCs, some of which may contribute to "sick building syndrome," and which have been shown to be toxigenic in a variety of laboratory bioassays. We hypothesized that VOCs from medically important fungi might be similarly toxigenic and tested strains of Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Cryptococcus gattii, and Saccharomyces cerevisiae in a Drosophila melanogaster eclosion bioassay. Fungi were grown in a shared microhabitat with third instar larvae of D. melanogaster such that there was no physical contact between flies and fungi. As the flies went through metamorphosis, the numbers of larvae, pupae, and adults were counted daily for 15 days. After 8 days, ~80% of controls had eclosed into adults and after 15 days the controls yielded 96-97% eclosion. In contrast, eclosion rates at 8 days were below 70% for flies exposed to VOCs from six different A. fumigatus strains; the eclosion rate at 15 days was only 58% for flies exposed to VOCs from A. fumigatus strain SRRC 1607. When flies were grown in a shared atmosphere with VOCs from S. cerevisiae, after 15 days, 82% of flies had eclosed into adults. Exposure to the VOCs from the medically important yeasts Candida albicans, Cryptococcus neoformans, and Cryptococcus gattii caused significant delays in metamorphosis with eclosion rates of 58% for Candida albicans, 44% for Cryptococcus neoformans, and 56% for Cryptococcus gattii. Using gas chromatography-mass spectrometry, the VOCs from the most toxic and least toxic strains of A. fumigatus were assayed. The two most common VOCs produced by both strains were 1-octen-3-ol and isopentyl alcohol; however, these compounds were produced in 10-fold higher concentrations by the more toxic strain. Our research demonstrates that gas phase compounds emitted by fungal pathogens may have been overlooked as contributing to the pathogenicity of medically important fungi and therefore deserve more scrutiny by the medical mycology research community.

Microbiological and chemical quality of indoor air in kindergartens in Slovenia

The concentrations of microorganisms, aerosol black carbon and carbon dioxide (CO₂) in indoor and outdoor air of two kindergartens were investigated during four seasons. The highest mean concentrations of aerobic mesophilic microorganisms in indoor air were detected in spring. Cladosporium, Penicillium and Aspergillus were the most common fungi in all air samples. The concentrations of Staphylococci, Enterobacteria and CO₂ had a positive correlation with the number of persons in the rooms. The highest mean concentration of black carbon in indoor and outdoor air was obtained in winter. Concentrations of CO₂ exceeded 1000 ppm in 89.3% of the indoor air measurements. The reduction of the number of children in individual playrooms and more frequent ventilation are recommended for lowering the concentration of CO₂ and the number of microorganisms in the air, especially potential pathogen fungi. The renovation of buildings with installation of effective artificial ventilation is recommended as well.Abbreviations: CFU, Colony-Forming Unit; HPC, Heterotrophic Plate Count (Aerobic Mesophilic Microorganisms); YGC, Yeast Extract Glucose Chloramphenicol Agar; BC, Aerosol Black Carbon Particles; CO₂, Carbon Dioxide; PM, Particulate Matter.

A cerium-based MOFzyme with multi-enzyme-like activity for the disruption and inhibition of fungal recolonization

A cerium-based metal–organic framework (Ce-MOF, denoted as AU-1) was synthesized using a solvothermal method by employing 4,4′,4′′-nitrilotribenzoic acid (H₃NTB) as the linker and cerium clusters as the metal center.

Seasonal diversity of biodeteriogenic, pathogenic, and toxigenic constituents of airborne mycobiota in a sacral environment

The main purpose of this study was to isolate airborne fungi and assess seasonal variations in air contamination with their particulates by determining the levels of their propagules in the nave and exonarthex of a church. We also monitored indoor microclimate as a determining factor for fungal proliferation on wall paintings, spore release, and transmission through the air. The temperature and relative humidity of the nave favoured fungal growth. A total of 33 fungi were isolated, mainly of the phylum Ascomycota, and to the lesser extent of the phyla Zygomycota and Basidiomycota. The most common were the fungi of the genera Penicillium and Aspergillus (23.55 % and 20.58 %, respectively). Sørensen's quotient of similarity (0.37) suggests moderate species overlap and constant exchange of fungal propagules between the nave and exonarthex. The autumn had the highest diversity, with 17 documented taxa, followed by the summer and the winter. The spring had only eight taxa. Quantitative analysis of the airborne mycobiota in the nave (430±84.85 to 1880±106.07 CFU m-3) and exonarthex (715±59.62 to 2295±91.92 CFU m-3) showed very high contamination throughout the year, with values exceeding the maximum permissible concentrations by most standards. Many of the fungi determined in this study are known for their biodeteriogenic, toxigenic, and allergenic properties, and are a threat not only to occasional visitors and staff, but also to valuable works of art decorating nave walls.

Volatile organic compounds from fungi isolated after hurricane katrina induce developmental defects and apoptosis in a Drosophila melanogaster model

In previous work, our laboratory developed a Drosophila model for studying the adverse effects of fungal volatile organic compounds (VOCs) emitted by growing cultures of molds. In this report, we have extended these studies and compared the toxic effects of fungal VOCs emitted from living cultures of four molds isolated after Hurricane Katrina from a flooded home in New Orleans. Strains of Aspergillus, Mucor, Penicillium, and Trichoderma were grown with wild-type larvae and the toxic effects of volatile products on the developmental stages of Drosophila larvae were evaluated. Furthermore, heterozygous mutants of Drosophila carrying the apoptotic genes, reaper and dronc, were used to assess the role of apoptosis in fungal VOCs mediated toxicity. Third-instar larvae of Drosophila carrying these apoptotic genes were exposed to fungal VOCs emitted from growing mold cultures for 10 days. The larval strains carrying apoptopic genes survived longer than the control wild type larvae; moreover, of those that survived, heterozygous reaper and dronc strains progressed to pupae and adult phases more rapidly, suggesting that fungal VOCs may induce apoptotic changes in flies. These data lend support to the use of Drosophila as an inexpensive and genetically versatile toxicological model to investigate the mechanistic basis for some of the human illnesses/symptoms associated with exposure to mold-contaminated indoor air, especially after hurricanes.

Microbiological quality of indoor air in university libraries

OBJECTIVE

To evaluate the concentration of bacteria and fungi in the indoor environment of Jimma University libraries, so as to estimate the health hazard and to create standards for indoor air quality control.

METHODS

The microbial quality of indoor air of eight libraries of Jimma University was determined. The settle plate method using open Petri-dishes containing different culture media was employed to collect sample twice daily. Isolates were identified according to standard methods.

RESULTS

The concentrations of bacteria and fungi aerosols in the indoor environment of the university libraries ranged between 367-2595 CFU/m(3). According to the sanitary standards classification of European Commission, almost all the libraries indoor air of Jimma University was heavily contaminated with bacteria and fungi. In spite of their major source difference, the average fungi density found in the indoor air of libraries did appear to follow the same trend with bacterial density (P=0.001). The bacteria isolates included Micrococcus sp., Staphylococcus aureus, Streptococcus pyogenes, Bacillus sp. and Neisseria sp. while Cladosporium sp., Alternaria sp., Penicillium sp. and Aspergillus sp. were the most isolated fungi.

CONCLUSIONS

The indoor air of all libraries were in the range above highly contaminated according to European Commission classification and the most isolates are considered as potential candidates involved in the establishment of sick building syndromes and often associated with clinical manifestations like allergy, rhinitis, asthma and conjunctivitis. Thus, attention must be given to control those environmental factors which favor the growth and multiplication of microbes in indoor environment of libraries to safeguard the health of users and workers.

Aspergillus section Versicolores: nine new species and multilocus DNA sequence based phylogeny

β-tubulin, calmodulin, internal transcribed spacer and partial lsu-rDNA, RNA polymerase 2, DNA replication licensing factor Mcm7, and pre-rRNA processing protein Tsr1 were amplified and sequenced from numerous isolates belonging to Aspergillus sect. versicolor. The isolates were analyzed phylogenetically using the concordance model to establish species boundaries. Aspergillus austroafricanus, A. creber, A. cvjetkovicii, A. fructus, A. jensenii, A. puulaauensis, A. subversicolor, A. tennesseensis and A. venenatus are described as new species and A. amoenus, A. protuberus,A. sydowii, A. tabacinus and A. versicolor are accepted as distinct species on the basis of molecular and phenotypic differences. PCR primer pairs used to detect A. versicolor in sick building syndrome studies have a positive reaction for all of the newly described species except A. subversicolor.

Indoor Exposure to Mould Allergens

Humid indoor environments may be colonised by allergenic filamentous microfungi (moulds),Aspergillusspp.,Penicilliumspp.,Cladosporiumspp., andAlternariaspp. in particular. Mould-induced respiratory diseases are a worldwide problem. In the last two decades, mould allergens and glucans have been used as markers of indoor exposure to moulds. Recently, mould allergens Alt a 1 (Alternaria alternata) and Asp f 1 (Aspergillus fumigatus) have been analysed in various environments (residential and occupational) with enzyme-linked immunosorbent assays, which use monoclonal or polyclonal antibodies. Household Alt a 1 and Asp f 1 levels were usually under the limit of the method detection. By contrast, higher levels of mould allergens were found in environments with high levels of bioaerosols such as poultry farms and sawmills. Data on allergen Alt a 1 and Asp f 1 levels in agricultural settings may provide information on possible colonisation of respective moulds and point out to mould-related diseases in occupants.

Relationships between mite allergen levels, mold concentrations, and sick building syndrome symptoms in newly built dwellings in Japan

This study investigated the possible relationships between exposures to mite allergen and airborne fungi with sick building syndrome (SBS) symptoms for residents living in newly built dwellings. We randomly sampled 5709 newly built dwellings in six prefectures from northern to southern Japan. A total of 1479 residents in 425 households participated in the study by completing questionnaire surveys and agreeing to environmental monitoring for mite allergen (Der 1), airborne fungi, aldehydes, and volatile organic compounds. Stepwise logistic regression analyses adjusted for confounders were used to obtain odds ratios (OR) of mite allergen and fungi for SBS symptoms. Der 1 had a significantly high OR for nose symptoms. Rhodotorula had a significantly high OR for any symptoms, and Aspergillus had significantly high OR for eye symptoms. However, the total colony-forming units had a significantly low OR for throat and respiratory symptoms. Eurotium had a significantly low OR for skin symptoms. In conclusion, dust-mite allergen levels and indoor airborne Rhodotorula and Aspergillus concentrations may result in SBS symptoms in newly built dwellings.

PRACTICAL IMPLICATIONS

Various factors can cause sick building syndrome symptoms. This study focused on biologic factors such as dust-mite allergen and airborne fungi in newly built dwellings in Japan. Dust-mite allergen levels were significantly associated with higher rates of nose symptoms, airborne Rhodotorula concentrations were significantly associated with higher rates of any symptoms, and Aspergillus concentrations were significantly associated with higher rates of eye symptoms. Measures should be taken to reduce mite allergen levels and fungal concentrations in these dwellings.

Microbiological monitoring of mineral water commercialized in Brazil

The quality of mineral water commercialized in Brazil regarding the microbial content was analyzed and the results were compared with the standards established by the current legislation. Results demonstrated there was no bacterial contamination, but several types of fungi were found. Therefore, bottled mineral water could be considered a possible route for the transmission of filamentous fungi and yeasts.

Murine models of airway fungal exposure and allergic sensitization

Inhalation of common indoor filamentous fungi has been associated with the induction or exacerbation of allergic respiratory disease. The understanding of fungal inhalation and allergic sensitization has significantly advanced with the use of small animal models, especially mouse models. Numerous studies have employed different animal exposure and sensitization techniques, each with inherent advantages and disadvantages that are addressed in this review. In addition, most studies involve exposure of animals to fungal spores or spore extracts while neglecting the influence of hyphal or subcellular fragment exposures. Recent literature examining the potential for hyphae and fungal fragments to induce or exacerbate allergy is discussed. Innate immune recognition of fungal elements and their contribution to lung allergic inflammation in animal models are also reviewed. Though physical properties of fungi play an important role following exposure, host immune development is also critical in airway inflammation and allergy. We discuss the importance of environmental factors that influence early immune development and subsequent susceptibility to allergy. Murine studies that examine the role of intestinal microflora and prenatal or early life environmental factors that promote allergic sensitization are also evaluated. Future studies will require animal models that accurately reflect natural fungal exposures and identify environmental factors that influence immune development and thus promote respiratory fungal allergy and disease.

Assessment of the presence and dynamics of fungi in drinking water sources using cultural and molecular methods

A comparison of different isolation techniques and culture media for detection of filamentous fungi and yeasts in the aquatic environment revealed that the use of membrane filtration with the media dichloran rose bengal chloramphenicol (DRBC) optimized fungi detection in terms of abundance and variety in three untreated water sources with very different characteristics (surface water, spring water, and groundwater). The diversity of the fungi population captured by direct DNA extraction of fungi collected by membrane filtration was compared with the isolates obtained after selective growth using different culture media through amplification of the internal transcribed spacer gene and denaturing gradient gel electrophoresis (DGGE). The Czapek-Dox agar, Sabouraud dextrose agar, and DRBC media showed closer similarities to those obtained by the uncultured biomass for the different water sources. Based on these data and the best enumeration results, DRBC is recommended for the assessment of fungi in water sources using culture-based methods. DGGE was also used to monitor temporal variations in the fungal population structure and showed that each water matrix possessed a distinct population profile as well as that changes in the fungal community can be expected in the different matrices throughout the year.

Microbiological Control of Flour-Manufacture: Dissemination of Mycotoxins Producing Fungi in Cereal Products

Wheat grain and its products are widely consumed as fodder and basic daily food stuffs in Kyrgyzstan. Mycobiota is known to produce hazardous effects to a consumer since it produces mycotoxins. Henceforth, mycobiota starting from the field stage to flour, grain and flour samples were selected for mycological analysis from eight sites of flour manufacture: grain stored in storehouses before milling, mechanically cleaned grain, washed grain, grain dried and prepared for mill, roughly-milled flour, first grade flour and high grade flour. The samples were analyzed using classical mycological and immunoassay methods in order to detect mycotoxins producing fungi species. We isolated overall 27 species belonging to 7 genera. Mycotoxins producing species like Aspergillus flavus, Aspergillus ochraceus and Penicillium cyclopium were detected in the stored grains and in mechanically-cleaned grains. The species of Penicillium, Alternaria and Fusarium genera dominated in roughly-milled flour samples, so this site of flour manufacture still has a risk and danger of contamination with mycotoxins producing fungus. Only the final product i.e. the high grade flour lacked any fungal contamination. We recommend to scrutinize flour samples at the last stages of processing, particularly in the mills like B1, C1 and C4.

Assessment of microbiological indoor air quality in an Italian office building equipped with an HVAC system

The purpose of this study was to evaluate the level and composition of bacteria and fungi in the indoor air of an Italian office building equipped with a heating, ventilation and air conditioning (HVAC) system. Airborne bacteria and fungi were collected in three open-space offices during different seasons. The microbial levels in the outdoor air, supply air diffusers, fan coil air flow and air treatment unit humidification water tank were used to evaluate the influence of the HVAC system on indoor air quality (IAQ). A medium-low level of bacterial contamination (50-500 CFU/m(3)) was found in indoor air. Staphylococcus and Micrococcus were the most commonly found genera, probably due to human presence. A high fungal concentration was measured due to a flood that occurred during the winter. The indoor seasonal distribution of fungal genera was related to the fungal outdoor distribution. Significant seasonal and daily variation in airborne microorganisms was found, underlining a relationship with the frequency of HVAC system switching on/off. The results of this monitoring highlight the role of the HVAC system on IAQ and could be useful to better characterise bacterial and fungal population in the indoor air of office buildings.

The biocontaminants and complexity of damp indoor spaces: more than what meets the eyes

Nine types of biocontaminants in damp indoor environments from microbial growth are discussed: (1) indicator molds; (2) Gram negative and positive bacteria; (3) microbial particulates; (4) mycotoxins; (5) volatile organic compounds, both microbial (MVOCs) and non-microbial (VOCs); (6) proteins; (7) galactomannans; (8) 1-3-β-D-glucans (glucans) and (9) lipopolysaccharides (LPS — endotoxins). When mold species exceed those outdoors contamination is deduced. Gram negative bacterial endotoxins, LPS in indoor environments, synergize with mycotoxins. The gram positive Bacillus species, Actinomycetes (Streptomyces, Nocardia and Mycobacterium), produce exotoxins. The Actinomycetes are associated with hypersensitivity pneumonitis, lung and invasive infections. Mycobacterial mycobacterium infections not from M. tuberculosis are increasing in immunocompetent individuals. In animal models, LPS enhance the toxicity of roridin A, satratoxins G and aflatoxin B1 to damage the olfactory epithelium, tract and bulbs (roridin A, satratoxin G) and liver (aflatoxin B1). Aflatoxin B1 and probably trichothecenes are transported along the olfactory tract to the temporal lobe. Co-cultured Streptomyces californicus and Stachybotrys chartarum produce a cytotoxin similar to doxorubicin and actinomycin D (chemotherapeutic agents). Trichothecenes, aflatoxins, gliotoxin and other mycotoxins are found in dust, bulk samples, air and ventilation systems of infested buildings. Macrocyclic trichothecenes are present in airborne particles <2 μm. Trichothecenes and stachylysin are present in the sera of individuals exposed to S. chartarum in contaminated indoor environments. Haemolysins are produced by S. chartarum, Memnoniella echinata and several species of Aspergillus and Penicillium. Galactomannans, glucans and LPS are upper and lower respiratory tract irritants. Gliotoxin, an immunosuppressive mycotoxin, was identified in the lung secretions and sera of cancer patients with aspergillosis produced by A. fumigatus, A. terreus, A. niger and A. flavus.

The study of fungi in drinking water

The occurrence of fungi in drinking water has received increased attention in the last decades, and fungi are now generally accepted as drinking water contaminants. The knowledge about the occurrence and diversity of fungi in water has increased considerably from a low knowledge base. However, the relevance of waterborne fungi for water quality and human health is poorly understood and still conflicting. Scientific reports on effective treatment against fungi in water are also few. This article presents a review of the literature on fungal water studies, including some general results, and considerations of significance, limits, contradictions, precautions, and practical consequences.

Diversity and significance of mold species in Norwegian drinking water

In order to determine the occurrence, distribution, and significance of mold species in groundwater- and surface water-derived drinking water in Norway, molds isolated from 273 water samples were identified. Samples of raw water, treated water, and water from private homes and hospital installations were analyzed by incubation of 100-ml membrane-filtered samples on dichloran-18% glycerol agar. The total count (number of CFU per 100 ml) of fungal species and the species diversity within each sample were determined. The identification of mold species was based on morphological and molecular methods. In total, 94 mold species belonging to 30 genera were identified. The mycobiota was dominated by species of Penicillium, Trichoderma, and Aspergillus, with some of them occurring throughout the drinking water system. Several of the same species as isolated from water may have the potential to cause allergic reactions or disease in humans. Other species are common contaminants of food and beverages, and some may cause unwanted changes in the taste or smell of water. The present results indicate that the mycobiota of water should be considered when the microbiological safety and quality of drinking water are assessed. In fact, molds in drinking water should possibly be included in the Norwegian water supply and drinking water regulations.