Identification of saprophytic and allergenic fungi in indoor and outdoor environments

Metabarcode insights into the airborne fungal diversity in the indoor and outdoor environments in archives from Yunnan, Southwestern China

Monitoring dynamics of airborne fungal species and controlling of harmful ones are of vital importance to conservation of cultural relics. However, the evaluation of air quality and the community structure characteristics of microorganisms, especially fungi, in the atmosphere of archives is in a stage of continuous exploration though more than 4,000 archives were constructed in China. Seventy-two air samples were collected in this study under different spatial and weather conditions from the archives of Kunming Medical University, located in the Kunming metropolitan area, Yunnan province, southwestern China. A total of 22 airborne fungal classes, 160 genera and 699 ASVs were identified, the species diversity is on the rise with the strengthening of air circulation with the outside space, and thus the intensive energy metabolism and activity were found in the spaces with window and sunny weather, except for the higher lipid synthesis of indoor samples than that of outdoor ones. Furthermore, there were significant differences in fungal community composition and abundance between sunny and rainy weathers. A considerable number of species have been identified as indicator in various environmental and weather conditions of the archives, and temperature and humidity were thought to have significant correlations with the abundance of these species. Meanwhile, Cladosporium and Alternaria were the dominant genera here, which may pose a threat to the health of archive professionals. Therefore, monitoring and controlling the growth of these fungal species is crucial for both conservation of paper records and health of archive professionals.

Exploring airborne fungal contaminations and air quality pollution in nine ancient stone temples, Surin, Thailand

This study provided crucial insights into the concentrations of airborne fungi, environmental parameters, and atmospheric pollution in Thailand's ancient stone temples. Airborne fungi were identified based on morphological characteristics. Airborne fungi, meteorological parameters, and atmospheric pollutants concurrently assessed during each sampling event, evaluating indoor/outdoor ratio. Prevalent genera included Penicillium (14.36%), Aspergillus (10.94%), Cladosporium (10.74%), Rhizopus (6.31%), and Fusarium (5.90%), with an average fungi concentration of 4884.46 ± 724.79 CFU/m3. Eighteen fungal species out of the 64 airborne fungi identified were well-known serious pathogenic agents, contributing not only to structural deterioration but also to human health. Significant variations were observed between indoor and outdoor environments and across diverse landscapes, particularly for PM10 (ranging from 43.47 to 121.31 µg/m3) and PM2.5 (ranging from 29.59 to 89.60 µg/m3), with intensive incense burning identified as a prominent source of indoor atmospheric pollution. Historical temples, particularly situated in urban areas, were identified as significant reservoirs of airborne fungi. Correlations between meteorological parameters and pollutants revealed strong associations. Furthermore, principal component analysis (PCA) and cluster analysis elucidated distinct patterns in airborne fungal concentrations and contaminations. This study analyzed environmental factors, pollutants, airborne fungi, and geographical variations from July 2020 to March 2021. Understanding prevalent genera, airborne fungi concentrations, pathogenic species, biodeterioration, and environmental dynamics provided strategies for improving indoor air quality and mitigating airborne fungal contamination in archaeological buildings worldwide.

The changing trend of fungal infection in invasive rhinosinusitis in the COVID era

Background

SARS-COV virus operates as a significant risk factor for invasive fungal aspergillosis and mucormycosis. Successful management of this fulminant infection requires early recognition of the disease and aggressive medical or surgical interventions to prevent the high morbidity and mortality associated with the disease process.

Aims and Objective of the Study

1. To isolate and identify different species of fungi among acute rhinosinusitis patients. 2. To assess the association of risk factors causing fungal rhinosinusitis. 3. To assess the changing trend in fungal rhinosinusitis during the COVID era.

Material and Methods

This is a retrospective observational study conducted from May 2020 to October 2022, attending the ENT department and relevant data were collected from the medical records department of ABVIMS and Dr RML Hospital, New Delhi, a Tertiary Care Referral Centre in India. The major risk factors studied were age, gender, COVID-19 infection and underlying diseases (such as diabetes mellitus, ischaemic heart disease, hypertension, malignancies, chronic kidney DISEASES, etc.); details of corticosteroid use of all patients were recorded in the datasheet. The pandemic data was divided into three distinct time periods/waves/eras, i.e., first, second, and third waves, each of which included ten months, to examine the changing trend in fungal rhinosinusitis in the pandemic era of COVID-19.

Results

A total of 412 patients out of which 236 patients were clinically diagnosed with fungal sinusitis based on revised EORTC criteria. The most common site involved was the orbit with paranasal sinus and eye 86/236 (36.4%), followed by involvement of nasal and paranasal sinus alone 68/236 (28.8%). The most prevalent age range affected was 40 to 50 years. The most commonly associated comorbidity was diabetes mellitus (DM) in 176 (74.5%), followed by head and neck malignancies in 22 (9.32%) patients. Thirty-eight (50.6%) Rhizopus species and 18 (24%) Aspergillus flavus were the most common isolated fungal species on culture, followed by Mucor spp. 14 (18.6%) and Aspergillus fumigatus 5 (6.6%) in the period. In the second wave of COVID, there was a surge in Zygomycetes cases 36 (45%) and after the second wave, the Aspergillus cases increased by 14 (19%) during Jan-Oct 2022.

Conclusion

With the continuing coronavirus pandemic, there is an unprecedented and discernible rise in the prevalence of acute invasive fungal sinusitis certainly a spike in cases of Aspergillus infection was observed, probably due to unprecedented usage of Amphotericin B for the treatment of mucormycosis during the third wave This underlines the importance of the need to tailor our treatment protocol as per the etiological agents hence the right antifungal drugs combined with urgent surgical procedures on a case-to-case basis may certainly increase the chances of survival.

The genus Acrophialophora: History, phylogeny, morphology, beneficial effects and pathogenicity

The genus Acrophialophora is a thermotolerant fungus, which is widely distributed in temperate and tropical zones. This fungus is classified in Ascomycota and belongs to the Chaetomiaceae family and the genera of Parathielavia, Pseudothielavia and Hyalosphaerella are closely related to Acrophialophora. For this genus have been reported 28 species so far, which two species of Acrophialophora jodhpurensis and Acrophialophora teleoafricana produce only sexual phase and other species produce asexual form. Therefore, producing both sexual and asexual forms were not reported by any species. Many applications were reported by some species in agriculture, pharmacy and industry. Production of enzymes, antimicrobial metabolites and plant growth-promoting factors were reported by some species. The species of A. nainiana is used in the industries of textile, fruit juice, pulp and paper due to extracellular enzyme production. Also, other species produce extracellular enzymes that can be used in various industries. The species Acrophialophora are used in the composting industry due to the production of various enzymes and to be thermotolerant. In addition, some species were isolated from hostile environmental conditions. Therefore has been suggested that it can be used for mycoremediation. Also, antimicrobial metabolites of Acrophialophora have been reported to be effective against human and plant pathogens. In contrast to the beneficial effects described, the Acrophialophora pathogenicity has been rarely reported. Two species A. fusispora and A. levis are opportunistic fungi and have been reported as pathogens in humans, animals and plants. Currently, the development and applications of Acrophialophora species have increased more than past. To our knowledge, there is no report with comprehensive information on the species of Acrophialophora, which include their disadvantage and beneficial effects, particularly in agriculture. Therefore, it seems necessary to pay more in-depth attention to the application of this genus as a beneficial fungus in agriculture, pharmaceutical and industry. This review is focused on the history, phylogeny, morphology, valuable roles of Acrophialophora and pathogenicity.

New generation sequencing: molecular approaches for the detection and monitoring of bioaerosols in an indoor environment: a systematic review

INTRODUCTION

The exposure of occupants to indoor air pollutants has increased in recent decades. The aim of this review is to discuss an overview of new approaches that are used to study fungal aerosols. Thus, this motivation was to compensate the gaps caused by the use of only traditional approaches in the study of fungal exposure.

CONTENT

The search involved various databases such as; Science Direct, PubMed, SAGE, Springer Link, EBCOHOST, MEDLINE, CINAHL, Cochrane library, Web of Science and Wiley Online Library. It was limited to full text research articles that reported the use of non-viable method in assessing bioaerosol, written in English Language, full text publications and published from year 2015-2022.

SUMMARY AND OUTLOOK

A total of 15 articles met the inclusion criteria and was included in this review. The use of next-generation sequencing, which is more commonly referred to as high-throughput sequencing (HTS) or molecular methods in microbial studies is based on the detection of genetic material of organisms present in a given sample. Applying these methods to different environments permitted the identification of the microorganisms present, and a better comprehension of the environmental impacts and ecological roles of microbial communities. Based on the reviewed articles, there is evidence that dust samples harbour a high diversity of human-associated bacteria and fungi. Molecular methods such as next generation sequencing are reliable tools for identifying and tracking the bacterial and fungal diversity in dust samples using 18S metagenomics approach.

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

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

Aspergillus Endophthalmitis: Epidemiology, Pathobiology, and Current Treatments

Fungal endophthalmitis is one of the leading causes of vision loss worldwide. Post-operative and traumatic injuries are major contributing factors resulting in ocular fungal infections in healthy and, more importantly, immunocompromised individuals. Among the fungal pathogens, the Aspergillus species, Aspergillus fumigatus, continues to be more prevalent in fungal endophthalmitis patients. However, due to overlapping clinical symptoms with other endophthalmitis etiology, fungal endophthalmitis pose a challenge in its diagnosis and treatment. Hence, it is critical to understand its pathobiology to develop and deploy proper therapeutic interventions for combating Aspergillus infections. This review highlights the different modes of Aspergillus transmission and the host immune response during endophthalmitis. Additionally, we discuss recent advancements in the diagnosis of fungal endophthalmitis. Finally, we comprehensively summarize various antifungal regimens and surgical options for the treatment of Aspergillus endophthalmitis.

Fungal Diversity in Two Wastewater Treatment Plants in North Italy

In urban wastewater treatment plants, bacteria lead the biological component of the depuration process, but the microbial community is also rich in fungi (mainly molds, yeasts and pseudo-yeasts), whose taxonomical diversity and relative frequency depend on several factors, e.g., quality of wastewater input, climate, seasonality, and depuration stage. By joining morphological and molecular identification, we investigated the fungal diversity in two different plants for the urban wastewater treatment in the suburbs of the two major cities in Lombardia, the core of industrial and commercial activities in Italy. This study presents a comparison of the fungal diversity across the depuration stages by applying the concepts of α-, β- and ζ-diversity. Eurotiales (mainly with Aspergillus and Penicillium), Trichosporonales (Trichosporon sensu lato), Saccharomycetales (mainly with Geotrichum) and Hypocreales (mainly with Fusarium and Trichoderma) are the most represented fungal orders and genera in all the stages and both the plants. The two plants show different trends in α-, β- and ζ-diversity, despite the fact that they all share a crash during the secondary sedimentation and turnover across the depuration stages. This study provides an insight on which taxa potentially contribute to each depuration stage and/or keep viable propagules in sludges after the collection from the external environment.

Invasive Aspergillosis of Nose and Paranasal Sinus in COVID-19 Convalescents: Mold Goes Viral?

Invasive Aspergillosis of the paranasal sinus is an aggressive illness, particularly affecting the immunocompromised and rarely, the immunocompetent. COVID-19 has been shown to cause a derangement of immune parameters both during active infection and the convalescent period. A retrospective study was done from June 10th 2021 to September 10th 2021 on patients who underwent endoscopic debridement of the involved sinuses for post COVID fungal rhinosinusitis. This study included the patients who had Aspergillus infection from the isolated nasal tissue samples. Patient’s information, complaints, history of COVID infection, clinical findings, investigations and treatment details were obtained from the records. 13 patients with post-COVID Invasive Fungal Sinusitis were identified. Symptom onset usually occurred within 1 month of COVID 19 diagnosis in all the patients. Nasal obstruction (84%) and headache (61%) were the most common symptoms. Computerized tomography imaging showed maxillary sinus involvement in all patients followed by ethmoid sinus in 76% of patients. Microbiological diagnosis and histopathological confirmation of Aspergillus species was done. All 13 patients underwent endoscopic debridement of the involved sinuses followed by anti-fungal therapy with Posaconazole. All responded well to the treatment with no recurrence till date. Admist an infinite number of Mucormycosis cases in this era of COVID-19 pandemic, we experienced a surge of Aspergillus infection during this second wave. Presentation at a young age, with no known co-morbidities, with minimal symptoms and history of COVID-19 infection are some of the important aspects to be considered in this series. A better morbidity outcome is expected when early detection and treatment is made in patients with post Covid-19 viral illness with Aspergillosis of nose and paranasal sinus.

Contribution of Visible Surface Mold to Airborne Fungal Concentration as Assessed by Digital Image Quantification

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.

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

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

Characterization of fungal aerosol in a landfill and an incineration plants in Guangzhou, Southern China: The link to potential impacts

To understand the characteristics and potential impacts of fungal aerosols in waste disposal treatments, we performed observations at a landfill and an incineration plants in Guangzhou, Southern China. Size-segregated airborne fungal concentrations were measured based on culture-dependent method, and fungal compositions in PM_2.5 were obtained using high-throughput sequencing method. Concentrations of airborne fungi varied from 376 to 9318 CFU/m³ in the landfill plant and from 53 to 8491 CFU/m³ in the incineration plant, respectively. The temporal and spatial variations of fungal aerosols indicate that waste disposal operation, garbage transport, air mixing, and meteorological factors can significantly influence the variations of airborne fungi in the outdoor environment in both plants. Among the meteorological factors, light/moderate rain could significantly increase the airborne fungal concentrations while heavy rain could decrease the concentrations due to wet scavenge. We observed that culturable fungal aerosols predominantly resided in the size range of 2.1-3.3 μm. Different fungal community structures in PM_2.5 were found between the landfill and the incineration plants, suggesting the influence of different waste sorts and treatment procedures. We further identified the pathogenic/allergenic fungal taxa (e.g., Alternaria, Epicoccum sp. and Stachybotrys sp.) in the two plants, implying the potential human health risks with long-term exposure for on-site workers and surrounding residents. The fungal genera producing microbial volatile organic compounds (MVOCs, e.g., Cladosporium, Fusarium sp., Penicillium sp. and Candida) were found in both plants. These MVOCs generation related fungal genera could contribute to the odor in the plants and, more importantly, affect the downwind area after aerosolization and transportation.

Biochemical Characteristics and Allergenic Activity of Common Fungus Allergens

Fungi form a large kingdom with more than 1.5 million species. Fungal spores are universal atmospheric components and are generally recognized as important causes of allergic disorders, including allergic rhinitis, allergic rhinosinusitis, asthma, and allergic bronchopulmonary aspergillosis. The 4 genera which have the closest connection with allergic disorder are Cladosporium, Alternaria, Aspergillus and Penicillium. The cDNA sequences of many fungi allergens and the amino acids involved in their immunoglobulin E binding and T-cell activation have already been elucidated. Until now, 111 allergens from 29 fungal genera have been approved by the International Allergen Nomenclature Sub-committee. This review mainly focuses on the biochemical characteristics and allergenic activity of important allergens from common environmental fungi.

The pheromone response module, a mitogen-activated protein kinase pathway implicated in the regulation of fungal development, secondary metabolism and pathogenicity

Mitogen-activated protein kinase (MAPK) pathways are highly conserved from yeast to human and are required for the regulation of a multitude of biological processes in eukaryotes. A pentameric MAPK pathway known as the Fus3 pheromone module was initially characterised in Saccharomyces cerevisiae and was shown to regulate cell fusion and sexual development. Individual orthologous pheromone module genes have since been found to be highly conserved in fungal genomes and have been shown to regulate a diverse array of cellular responses, such as cell growth, asexual and sexual development, secondary metabolite production and pathogenicity. However, information regarding the assembly and structure of orthologous pheromone modules, as well as the mechanisms of signalling and their biological significance is limited, specifically in filamentous fungal species. Recent studies have provided insight on the utilization of the pheromone module as a central signalling hub for the co-ordinated regulation of fungal development and secondary metabolite production. Various proteins of this pathway are also known to regulate reproduction and virulence in a range of plant pathogenic fungi. In this review, we discuss recent findings that help elucidate the structure of the pheromone module pathway in a myriad of fungal species and its implications in the control of fungal growth, development, secondary metabolism and pathogenicity.

Molecular, physiological, and biochemical characterization of extracellular lipase production by Aspergillus niger using submerged fermentation

Background

Extracellular production of fungal lipases especially the lipases obtained from the Aspergilli has gained immense interest in recent years due to its diverse biotechnological applications. In this study, we focused on determining the fermentation parameters required for the optimal lipase production.

Methods

A total of 256 fungal isolates were obtained from oil seeds. From each genus, one isolate was selected to evaluate lipase production using phenol red and tributyrin plate assays. Lipase activity was estimated using the spectrophotometric pNPP hydrolysis assay. The highest lipase producer isolates were identified using 18S ribosomal RNA gene sequencing. The genetic variability was determined by random amplified polymorphic DNA (RAPD) analysis and the dendrogram was constructed using the unweighted pair group method with arithmetic averages method. The isolates were examined in a submerged fermentation culture (Smf) to measure the effect of temperature, pH, incubation time, carbon source, nitrogen source, inoculum volume, and lipid source on lipase production.

Results

Eleven isolates belonging to the genus Aspergillus were analyzed for lipase production where they were found to be the highest lipase producers among various fungal genera. All the tested isolates were identified as A. niger using 18s rRNA sequencing. Genetic diversity was evaluated among all of the studied A. niger isolates using RAPD primers. The RAPD primers were used to amplify 285 loci, of which five were polymorphic (1.75%) and seven were monomorphic (2.45%). Thus, a high level of genetic diversity was observed among all isolates. The tributyrin test and the lipase activity assay identified five strains of A. niger as high lipase producers, and their optimal enzyme activities were 709.74, 532.54, 735.64, 794.62, and 787.69 U/ml. The optimal conditions for lipase production were as follows: 40 °C, pH 7.5, 1% fructose as the carbon source, 1% yeast extract as the nitrogen source, 2% palm oil, 2.5 × 10⁷ spores/ml suspension, and 3 days of incubation.

Conclusions

The current study provides a comprehensive characterization of the optimal conditions, which are essential to enhance lipase production in five A. niger isolates.

The Pathogenesis of Fungal-Related Diseases and Allergies in the African Population: The State of the Evidence and Knowledge Gaps

The prevalence of allergic diseases in the African continent has received limited attention with the allergic diseases due to fungal allergens being among the least studied. This lead to the opinion being that the prevalence of allergic disease is low in Africa. Recent reports from different African countries indicate that this is not the case as allergic conditions are common and some; particularly those due to fungal allergens are increasing in prevalence. Thus, there is need to understand both the aetiology and pathogenies of these diseases, particularly the neglected fungal allergic diseases. This review addresses currently available knowledge of fungal-induced allergy, disease pathogenesis comparing findings from human versus experimental mouse studies of fungal allergy. The review discusses the potential role of the gut mycobiome and the extent to which this is relevant to fungal allergy, diagnosis and human health.