The existence of airborne mycotoxins in mold-contaminated buildings has long been hypothesized to be a potential occupant health risk. However, little work has been done to demonstrate the presence of these compounds in such environments. The presence of airborne macrocyclic trichothecene mycotoxins in indoor environments with known Stachybotrys chartarum contamination was therefore investigated. In seven buildings, air was collected using a high-volume liquid impaction bioaerosol sampler (SpinCon PAS 450-10) under static or disturbed conditions. An additional building was sampled using an Andersen GPS-1 PUF sampler modified to separate and collect particulates smaller than conidia. Four control buildings (i.e., no detectable S. chartarum growth or history of water damage) and outdoor air were also tested. Samples were analyzed using a macrocyclic trichothecene-specific enzyme-linked immunosorbent assay (ELISA). ELISA specificity was tested using phosphate-buffered saline extracts of the fungal genera Aspergillus, Chaetomium, Cladosporium, Fusarium, Memnoniella, Penicillium, Rhizopus, and Trichoderma, five Stachybotrys strains, and the indoor air allergens Can f 1, Der p 1, and Fel d 1. For test buildings, the results showed that detectable toxin concentrations increased with the sampling time and short periods of air disturbance. Trichothecene values ranged from <10 to >1,300 pg/m 3 of sampled air. The control environments demonstrated statistically significantly (P < 0.001) lower levels of airborne trichothecenes. ELISA specificity experiments demonstrated a high specificity for the trichothecene-producing strain of S. chartarum. Our data indicate that airborne macrocyclic trichothecenes can exist in Stachybotrys-contaminated buildings, and this should be taken into consideration in future indoor air quality investigations.For the past 25 years, there has been growing concern about the presence of fungi and their adverse human health effects in indoor environments. Several genera of fungi, including Stachybotrys, Chaetomium, and Aspergillus, have raised particular concern because of their associated toxin production. To date, the majority of indoor air quality investigations have focused on analyses of mold growth on building materials (1,18,35,40) and measurements of airborne particulate matter, including dust, fungal conidia (6, 20), and animal danders (13). These types of investigations cannot directly assess occupant exposure to mycotoxins. Exposure to these factors can influence allergic hypersensitivity responses (2, 9, 29) and symptoms of asthma in certain individuals (11, 30) but most likely does not account for often-reported symptoms such as nausea, dizziness, nose bleeds, physical and mental fatigue, and neurological disorders (28, 39) seen in subjects occupying sick buildings.Among the many fungi isolated from contaminated indoor environments, Stachybotrys chartarum is one of the most well known. S. chartarum is a known producer of a number of potent mycotoxins, in particular the macrocyclic tricho...
The growth of indoor molds and their resulting products (e.g., spores and mycotoxins) can present health hazards for human beings. The efficacy of chlorine dioxide gas as a fumigation treatment for inactivating sick building syndrome-related fungi and their mycotoxins was evaluated. Filter papers (15 per organism) featuring growth of Stachybotrys chartarum, Chaetomium globosum, Penicillium chrysogenum, and Cladosporium cladosporioides were placed in gas chambers containing chlorine dioxide gas at either 500 or 1,000 ppm for 24 h. C. globosum was exposed to the gas both as colonies and as ascospores without asci and perithecia. After treatment, all organisms were tested for colony growth using an agar plating technique. Colonies of S. chartarum were also tested for toxicity using a yeast toxicity assay with a high specificity for trichothecene mycotoxins. Results showed that chlorine dioxide gas at both concentrations completely inactivated all organisms except for C. globosum colonies which were inactivated an average of 89%. More than 99% of ascospores of C. globosum were nonculturable. For all ascospore counts, mean test readings were lower than the controls (P < 0.001), indicating that some ascospores may also have been destroyed. Colonies of S. chartarum were still toxic after treatment. These data show that chlorine dioxide gas can be effective to a degree as a fumigant for the inactivation of certain fungal colonies, that the perithecia of C. globosum can play a slightly protective role for the ascospores and that S. chartarum, while affected by the fumigation treatment, still remains toxic.Sick building syndrome (SBS) is a broad term for a range of human health symptoms associated with poor indoor air quality. While poor indoor air quality can be related to a number of issues, the one that has received the most attention in the last 5 to 10 years has been the effects of airborne fungi and their products (2, 6, 12). It has been acknowledged that damp and moldy structures are potentially harmful to the occupants (16). Therefore, from a human health standpoint, it is recommended that the conditions that allowed for fungal proliferation inside human occupied structures be addressed and corrected and that existing fungal growth be removed or treated from any affected substrates. However, a problem is the detection of hidden mold growth sites. Invasive investigations can assist in this regard, but these investigations can be costly to effect and there is also the possibility that some growth sites can be overlooked. It is possible that gaseous fungicides may be able to circumvent this problem because the gas can penetrate into crevices, wall cavities and other hard to access areas, thus treating the inaccessible mold colonies. The contents inside a contaminated structure may also be able to be sterilized (10) using this technique as well. A biocide, chlorine dioxide, has been previously been used in a gaseous form for bacterial decontamination (1, 9). It has been also shown to have a degree of fungicidal activi...
An investigation was conducted on selected locations in air handling units (AHUs) to (a) identify common mold species found on these locations, (b) determine whether some locations (and subsets) featured mold growth sites more frequently than others, (c) ascertain whether the operating condition of AHUs is related to mold contamination, and (d) provide a basis for a microbial sampling protocol for AHUs. A total of 566 tape lifts and 570 swab samples were collected from the blower wheel fan blades, insulation, cooling coil fins, and ductwork from 25 AHUs. All AHU conditions were numerically rated using a heating, ventilation and air-conditioning (HVAC) survey. Results showed that Cladosporium sp. fungi were commonly recovered in terms of growth sites and deposited spores, and they were found mainly in the blower wheel fan blades, the ductwork, and the cooling coil fins. Subsections of the fan blades, insulation, and cooling coil fins showed no preferred area for mold growth sites. Other organisms such as Penicillium sp., Aspergillus sp., and Paecilomyces sp. were recovered from the cooling coil fins and insulation. Because of the widespread prevalence of Cladosporium sp., there was no relationship between mold growth and operating condition. However, the presence of different species of molds in locations other than the blower wheel blades may indicate that the AHU condition is not optimal. A suggested microbial sampling protocol including interpretations of sample results is presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.