Exploiting the Advantages of Molecular Tools for the Monitoring of Fungal Indoor Air Contamination: First Detection of Exophiala jeanselmei in Indoor Air of Air-Conditioned Offices

Abstract

Today, indoor air pollution is considered a public health issue. Among the impacting pollutants, indoor airborne fungi are increasingly highlighted. Most of the monitoring protocols are culture-based, but these are unable to detect the uncultivable and/or dead fraction or species suppressed by fast-growing fungi, even though this fraction could impact health. Among the contaminants suspected to be part of this fraction, Exophiala jeanselmei is an interesting case study. Known to be pathogenic, this black yeast grows in humid environments such as air-conditioning systems, where it has been previously detected using classical culture-based methods. However, until now, this fungus was never detected in indoor air in contact with these air-conditioning systems. This study shows the first detection of E. jeanselmei in indoor air collected from offices in contact with contaminated air-conditioning reservoirs. While its presence in indoor air could not be demonstrated with culture-based methods, it was found by real-time PCR and massive parallel sequencing. The latter also allowed obtaining a broader view on the fungal diversity in the tested samples. Similar approaches were applied on water samples collected from the conditioning reservoirs to trace the source of contamination. The comparison of results obtained with both methods confirmed that the molecular tools could improve indoor air monitoring, especially of dead and/or uncultivable contaminants or when competition between species could occur.

Diversity and molecular diagnostics of fungi and oomycetes in plants

“…The members of Herpotrichiellaceae have been collected from several sources worldwide. These consist of air, insects, lichens, plants, rocks, and soil (Diederich et al, 2013;Feng et al, 2014;Das et al, 2019;Libert et al, 2019;Lima et al, 2020;Thitla et al, 2022). In addition, numerous studies have reported that some herpotrichiellaceous fungi are opportunistic fungi in humans and other animals (Badali et al, 2008;de Hoog et al, 2011;.…”

Method for detection of pathogenic bacteria from indoor air microbiome samples using high-throughput amplicon sequencing

“…Traditionally, culture-dependent method has been used for sample collection, isolation, and identification of bacteria in the indoor air of hospitals [10] , [11] , [12] . However, this method had a few drawbacks, including require a large volume of air to be sampled for a period of time [13] laborious as it requires many media preparations and different types of culture media for bacteria cultivation and isolation, take longer time to obtain result as bacteria need to be cultivated and incubated prior to analysis, and accuracy of the results can be doubted because some bacteria present in indoor air could not be cultivated [14] .…”

Species Diversity, Distribution, and Phylogeny of Exophiala with the Addition of Four New Species from Thailand

“…This would indicate their capacity to adapt to different ecosystems as summarized in Table 1 . Several species have been found in various natural environments [ 3 , 18 , 21 , 22 , 23 , 24 , 25 , 26 ]. Some species have been isolated from anthropogenic places and objects (e.g., bathrooms, gasoline tanks of cars, washing machines, and kitchen sponges) [ 7 , 27 , 28 , 29 ].…”

“…There are 26 Exophiala species (41.3%) that have been reported as causal agents of human diseases [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , …”