An evaluation of antifungal agents for the treatment of fungal contamination in indoor air environments.

Senthaamarai Rogawansamy,Dino Pisaniello,Sharyn Gaskin,Michael Taylor

doi:10.3390/ijerph120606319

Senthaamarai Rogawansamy, Dino Pisaniello + Show 2 more

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https://doi.org/10.3390/ijerph120606319

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Abstract

Fungal contamination in indoor environments has been associated with adverse health effects for the inhabitants. Remediation of fungal contamination requires removal of the fungi present and modifying the indoor environment to become less favourable to growth. This may include treatment of indoor environments with an antifungal agent to prevent future growth. However there are limited published data or advice on chemical agents suitable for indoor fungal remediation. The aim of this study was to assess the relative efficacies of five commercially available cleaning agents with published or anecdotal use for indoor fungal remediation. The five agents included two common multi-purpose industrial disinfectants (Cavicide® and Virkon®), 70% ethanol, vinegar (4.0%−4.2% acetic acid), and a plant-derived compound (tea tree (Melaleuca alternifolia) oil) tested in both a liquid and vapour form. Tea tree oil has recently generated interest for its antimicrobial efficacy in clinical settings, but has not been widely employed for fungal remediation. Each antifungal agent was assessed for fungal growth inhibition using a disc diffusion method against a representative species from two common fungal genera, (Aspergillus fumigatus and Penicillium chrysogenum), which were isolated from air samples and are commonly found in indoor air. Tea tree oil demonstrated the greatest inhibitory effect on the growth of both fungi, applied in either a liquid or vapour form. Cavicide® and Virkon® demonstrated similar, although less, growth inhibition of both genera. Vinegar (4.0%–4.2% acetic acid) was found to only inhibit the growth of P. chrysogenum, while 70% ethanol was found to have no inhibitory effect on the growth of either fungi. There was a notable inhibition in sporulation, distinct from growth inhibition after exposure to tea tree oil, Virkon®, Cavicide® and vinegar. Results demonstrate that common cleaning and antifungal agents differ in their capacity to inhibit the growth of fungal genera found in the indoor air environment. The results indicate that tea tree oil was the most effective antifungal agent tested, and may have industrial application for the remediation of fungal contamination in residential and occupational buildings.

Highlights

Populations in developed countries spend more than 90% of their time indoors and the installation and maintenance of HVAC systems has become increasingly important
Tea tree oil applied as a direct contact solution was found to have the highest inhibitory effect on the growth of both A. fumigatus and P. chrysogenum after a seven-day incubation period compared to the other antifungal agents tested (Figure 1)
Tea tree oil (TTO) when applied in vapour form, was found to be less effective than direct application in inhibiting the growth of condidate fungi (A. fumigatus mean inhibition zone diameter of 81 mm ± 4; P. chrysogenum mean inhibition zone diameter of 20.6 mm ± 12.85 for the vapour assay)

Summary

Introduction

Populations in developed countries spend more than 90% of their time indoors and the installation and maintenance of HVAC (heating, ventilating, and air conditioning) systems has become increasingly important. Fungi have become one of the leading causes of indoor air quality (IAQ) complaints in occupational settings [1,2,3]. Fungi are frequently implicated as a causative agent in “sick building syndrome” [4] and fungal contamination of indoor environments has been linked to adverse health effects including headache, allergy, asthma, irritant effects, respiratory problems, mycoses (fungal diseases), and several other non-specific health problems [5]. More than 80 genera of fungi have been associated with symptoms of respiratory tract allergies with Cladosporium, Alternaria, Aspergillus and Penicillium amongst the most common allergenic genera [6]. Many fungi produce microbial volatile organic compounds (MVOCs) and mycotoxins that are believed to irritate the respiratory system. Research from animal studies and data from occupational settings have shown that exposure to mycotoxins can result in mucus membrane irritation, skin rashes, dizziness, nausea, and immunosuppression [7]

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