Diversity of Species and Susceptibility Phenotypes toward Commercially Available Fungicides of Cultivable Fungi Colonizing Bones of Ursus spelaeus on Display in Niedźwiedzia Cave (Kletno, Poland)

Abstract

Underground ecosystems are one of the most inhospitable places for microorganism development and function. Therefore, any organic matter located in these areas can stimulate fungal growth. The main purpose of this study was to find the best solution to effectively preserve (without relapses) paleolithic bones of cave bear (Ursus spelaeus) exhibited in cave without any negative influence on the cave environment. To achieve this aim, unambiguous identification of fungal species and its susceptibility tests toward fungicidal preparations were performed. Fungi were identified based on phenotypic tests and the internal transcribed spacer (ITS) region analysis. The antifungal activity of three preparations (Pufmax, Boramon and Devor Mousse) was evaluated by microdilution assay (protocol M38-A2) and spot tests assay. Phenotypic and molecular research showed that bones were colonized by 11 fungal species: Absidia glauca, Aspergillus fumigatus, Chrysosporium merdarium, Fusarium cerealis, Mortierella alpina, Mucor aligarensis, M. plumbeus, Penicillium chrysogenum, P. expansum, Sarocladium strictum and Scopulariopsis candida. All of the tested preparations were the most active against C. merdarium. In turn, M. plumbeus, M. aligarensis, M. alpina and A. glauca were the least susceptible. The highest antifungal activity was shown for Pufmax (minimum inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values were in the range of 0.16–0.63% and 1.25–2.50%, respectively). The lowest fungicidal effect was observed for Boramon (MICs and MFCs in the range of 2.5–10% and 5–20%, respectively). Devor Mousse and Pufmax preparations showed fungicidal activity at the concentrations in the range of 1.25–5%. Susceptibility profiles were also confirmed based on spot tests assay. Our study allows for unambiguously identifying isolated fungi and assessing their susceptibility to commercially available fungicides, to prevent fungal outbreak.