Over the past 20 years, exposure to mycotoxin producing mold has been recognized as a significant health risk. Scientific literature has demonstrated mycotoxins as possible causes of human disease in water-damaged buildings (WDB). This study was conducted to determine if selected mycotoxins could be identified in human urine from patients suffering from chronic fatigue syndrome (CFS). Patients (n = 112) with a prior diagnosis of CFS were evaluated for mold exposure and the presence of mycotoxins in their urine. Urine was tested for aflatoxins (AT), ochratoxin A (OTA) and macrocyclic trichothecenes (MT) using Enzyme Linked Immunosorbent Assays (ELISA). Urine specimens from 104 of 112 patients (93%) were positive for at least one mycotoxin (one in the equivocal range). Almost 30% of the cases had more than one mycotoxin present. OTA was the most prevalent mycotoxin detected (83%) with MT as the next most common (44%). Exposure histories indicated current and/or past exposure to WDB in over 90% of cases. Environmental testing was performed in the WDB from a subset of these patients. This testing revealed the presence of potentially mycotoxin producing mold species and mycotoxins in the environment of the WDB. Prior testing in a healthy control population with no history of exposure to a WDB or moldy environment (n = 55) by the same laboratory, utilizing the same methods, revealed no positive cases at the limits of detection.
Many fungi can develop on building material in indoor environments if moisture is high enough. Among species that are frequently observed, some are known to be potent mycotoxin producers. This presence of toxinogenic fungi in indoor environments raises the question of the possible exposure of occupants to these toxic compounds by inhalation after aerosolization.This study investigated the mycotoxin production by Penicillium brevicompactum, Aspergillus versicolor and Stachybotrys chartarum during their growth on wallpaper and the possible subsequent aerosolization of produced mycotoxins from contaminated substrates.We demonstrated that mycophenolic acid, sterigmatocystin and macrocyclic trichothecenes (sum of 4 major compounds) could be produced at levels of 1.8, 112.1 and 27.8 mg/m(2), respectively on wallpaper. Moreover, part of the produced toxins could be aerosolized from substrate. The propensity to aerosolization differed according to the fungal species. Thus, particles were aerosolized from wallpaper contaminated with P. brevicompactum when air velocity of just 0.3 m/s was applied, where S. chartarum required air velocity of 5.9 m/s. A versicolor was intermediate since aerosolization occurred under air velocity of 2 m/s.Quantification of the toxic content revealed that toxic load was mostly associated with particles of size equal or higher of 3 μm, which may correspond to spores. However, some macrocyclic trichothecenes (especially satratoxin H and verrucarin J) can also be found on smaller particles that can penetrate deeply in the respiratory tract upon inhalation. These elements are important for risk assessment related to mouldy environments.IMPORTANCE The possible colonisation of building material by toxinogenic fungi in case of moistening raises the question of the subsequent exposure of occupants to aerosolized mycotoxins. In this study, we demonstrated that three different toxinogenic species produce mycotoxins during their development on wallpaper. These toxins can subsequently be aerosolized, at least partly, from mouldy material. This transfer to air requires air velocities that can be encountered in « real life conditions » in buildings. The most part of the aerosolized toxic load is found in particles whose size corresponds to spores or mycelium fragments. However, some toxins were also found on particles smaller than spores that are easily respirable and can deeply penetrate into human respiratory tract. All these data are important for risk assessment related to fungal contamination of indoor environments.
It has recently been demonstrated that patients who develop chronic illness after prior exposure to water damaged buildings (WDB) and mold have the presence of mycotoxins, which can be detected in the urine. We hypothesized that the mold may be harbored internally and continue to release and/or produce mycotoxins which contribute to ongoing chronic illness. The sinuses are the most likely candidate as a site for the internal mold and mycotoxin production. In this paper, we review the literature supporting this concept.
Fusarium graminearum is the predominant causal species of Fusarium head blight in Europe and North America. Different chemotypes of the species exist, each producing a plethora of mycotoxins. Isolates of differing chemotypes produce nivalenol (NIV) and deoxynivalenol (DON), which differ in toxicity to mammals and plants. However, the effect of each mycotoxin on volatile emissions of plant hosts is not known. Host volatiles are interpreted by insect herbivores such as Sitobion avenae, the English grain aphid, during host selection. Previous work has shown that grain aphids are repelled by wheat infected with DON-producing F. graminearum, and this study seeks to determine the influence of pathogen mycotoxins to host volatile chemistry. Volatile collections from infected hosts and olfactometer bioassays with alate aphids were performed. Infections with isolates that produced DON and NIV were compared, as well as a trichothecene deficient transformant derived from the NIV-producing isolate. This work confirmed the repellent nature of infected hosts with DON accumulation. NIV accumulation produced volatiles that were attractive to aphids. Attraction did not occur when NIV was absent and was, therefore, a direct consequence of NIV production.
In the indoor environment people are exposed to several fungal species. Evident dampness is associated with increased respiratory symptoms. To examine immune responses associated with fungal exposure mice are often exposed to one species grown on an agar medium. The aim of this study was to develop an inhalation exposure system to be able to examine responses in mice to exposure to mixed fungal species aerosolised from fungal-infested building materials. Indoor airborne fungi were sampled and cultivated on gypsum boards. Aerosols were characterised and compared with aerosols in homes.Aerosols containing 10(7)cfu of fungi/m(3) air were generated repeatedly from fungal-infested gypsum boards in a mouse exposure chamber. Aerosols contained: Aspergillus nidulans, A.niger, A.ustus, A.versicolor, Chaetomium globosum, Cladosporium herbarum, Penicillium brevicompactum, P.camemberti, P.chrysogenum, P.commune, P.glabrum, P.olsonii, P.rugulosum, Stachybotrys chartarum and Wallemia sebi. They were all among the most abundant airborne species identified in 28 homes. Nine species from gypsum boards and 11 species in the homes are associated with water damage. Most fungi were present as single spores, but chains and clusters of different species and fragments were also present. The variation in exposure level during the 60 min of aerosol generation was similar to the variation measured in homes.Through aerosolisation of fungi, from the indoor environment, cultured on gypsum boards, it was possible to generate realistic aerosols in terms of species composition, concentration, and particle sizes. The inhalation-exposure system can be used to study: responses to indoor fungi associated with water damage and the importance of fungal species composition.
Contamination of agricultural commodities with multiple trichothecene mycotoxins, produced by toxigenic Fusarium species, is a food safety issue, which greatly affects grain production and marketing worldwide. Importantly, exposure to multiple trichothecenes may increase toxicity in animals due to their synergistic and/or additive effects. To address the problem this study aimed to achieve a novel biological trait capable of detoxifying various food and feed contaminating trichothecenes under aerobic and anaerobic conditions and wide range of temperatures.
Gypsum wallboard is a popular building material, but is also very frequently overgrown by Stachybotrys chartarum after severe and/or undetected water damage. The purpose of this study was to determine if Stachybotrys and other fungi frequently isolated from wet gypsum wallboard are already present in the panels directly from the factory. Surface disinfected gypsum discs were wetted with sterile water, sealed and incubated for 70 days. The results showed that Neosartorya hiratsukae (≡ Aspergillus hiratsukae) was the most dominant fungus on the gypsum wallboard followed by Chaetomium globosum and Stachybotrys chartarum. Our results suggest that these three fungal species are already embedded in the materials, presumably in the paper/carton layer surrounding the gypsum core, before the panels reach the retailers/building site. This article is protected by copyright. All rights reserved.
There are few studies on rhinitis and sick building syndrome (SBS) among students in tropical countries. We studied associations between levels of five fungal DNA sequences, two mycotoxins (sterigmatocystin and verrucarol) and cat allergen (Fel d 1) levels in schools and rhinitis and other weekly SBS symptoms in the students. Fungal DNA was measured by quantitative PCR and cat allergen by ELISA. Pupils (N = 462) from eight randomly selected schools in Johor Bahru, Malaysia participated (96%). Dust samples were collected by cotton swabs and Petri dishes exposed for one week. None of the schools had a mechanical ventilation system, but all classrooms had openable windows that were kept open during lectures and indoor CO2 levels were low (mean 492 ppm; range 380-690 ppm). Weekly nasal symptoms (rhinitis) (18.8%), ocular (11.6%), throat (11.1%), dermal symptoms, headache (20.6%) and tiredness (22.1%) were common. Total fungal DNA in swab samples was associated with rhinitis (p = 0.02), ocular symptoms (p = 0.009) and tiredness (p = 0.001). There were positive associations between Aspergillus versicolor DNA in Petri dish samples, ocular symptoms (p = 0.02) and tiredness (p = 0.001). The level of the mycotoxin verrucarol (produced by Stachybotrys chartarum) in swab samples was positively associated with tiredness (p = 0.04). Streptomyces DNA in swab samples (p = 0.03) and Petri dish samples (p = 0.03) were negatively associated with tiredness. In conclusion, total fungal contamination, measured as total fungal DNA) in the classrooms, Aspergillus versicolor and verrucarol can be risk factors for rhinitis and SBS symptoms among students in the tropical country Malaysia.
- International journal of environmental research and public health
- Published 4 months ago
Environmental sustainability is one of the key issues in building management. In Hong Kong, one of the initiatives is to reduce the operation hours of air-conditioning in buildings to cut down energy consumption. In this study, we reported a mold contamination case in a newly refurbished laboratory, in which the air-conditioner was switched from 24- to 18-h mode after refurbishment. In order to prevent mold recurrence, the air-conditioner was switched back to 24-h mode in the laboratory. During the mold investigation, visible mold patches in the laboratory were searched and then cultured, counted and identified. Building and environmental conditions were recorded, and used to deduce different causes of mold contamination. Eight contaminated sites including a wall, a bench, some metal and plastic surfaces and seven types of molds including twoCladosporiumspp., twoAspergillusspp., oneRhizopussp., oneTrichodermasp., and oneTritirachiumsp. were identified.Cladosporiumspp. were the most abundant and frequently found molds in the laboratory. The contaminated areas could have one to five different species on them. Based on the mold and environmental conditions, several scenarios causing the mold contamination were deduced, and different mold control measures were discussed to compare them with the current solution of using 24-h air-conditioning to control mold growth. This study highlights the importance of mold hygiene in sustainable building management.
In the course of gaining new insights into the secondary metabolite profile of various Stachybotrys strains, in particular concerning triprenyl phenol-like compounds, so far, unknown metabolites with analogous structural features were discovered. Three novel meroterpenoids containing a chromene ring moiety, namely stachybotrychromenes A-C, were isolated from solid culture of the filamentous fungus Stachybotrys chartarum DSMZ 12880 (chemotype S). Their structures were elucidated by means of comprehensive spectroscopic analysis (1D and 2D NMR, ESI-HRMS, and CD) as well as by comparison with spectroscopic data of structural analogues described in literature. Stachybotrychromenes A and B exhibited moderate cytotoxic effects on HepG2 cells after 24 h with corresponding IC50values of 73.7 and 28.2 μM, respectively. Stachybotrychromene C showed no significant cytotoxic activity up to 100 μM. Moreover, it is noteworthy that stachybotrychromenes A-C are produced not only by S. chartarum chemotype S but also S. chartarum chemotype A and Stachybotrys chlorohalonata.