What do we know about the associated mycobiota of the built environment?

The list of fungal species reported to be associated with the built environment is long, even when broken down to comparable building characteristics. The reason is that surveys are very diverse in terms of sampling methods, identification protocols and environmental conditions. Moreover, the rapid development in taxonomic schemes is a major challenge. The phylogenetic species concept splits ‘old’ indoor related species of e.g. Aspergillus, Penicillium, and Cladosporium into numerous new species, often delimitated by differences in gene sequences only. The methods used for detection and identification are frequently updated and fine-tuned, but there will always be a lag-time before implementation is completed. Consequently, many reports and scientific papers on the mycobiota are using yesterday’s species concept, which may be beneficial as there is a substantial body of knowledge describing the functionality and ecology of yesterday’s species. However, an updated sequenced based identification will generate results based on today’s species concept where no or limited information on physiology, toxicology, ecology etc. is present. The modern molecular tools are getting faster and faster, but the functional characterization of taxonomic novelties cannot match the pace of the taxonomic development. The result is a crucial loss of knowledge of important indoor related species of Aspergillus, Penicillium and Cladosporium and several examples will demonstrate this unfortunate situation. The outcome is that many descriptive scientific papers contain long lists of fungal species detected; but what do these results tell us about the mycobiota of built environment or health impact? In most cases, nothing or only speculations that reflect the limited body of knowledge of today’s species. The knowledge gaps represent an overwhelming amount of different types of very important data, far too much for a single research unit to cope with. It is proposed to develop and launch an international infrastructure that supports compilation of data on functionality of the fungal species. Ideally, in an open and easy accessible set-up e.g. like GenBank, and with the possibility to link between databanks to support a much better and deeper understanding of the mycobiota of the built environment and its impact on human health.