Re-defining the culturing method for Pseudogymnoascus destructans incorporating viability detection.

Pseudogymnoascus destructans (Pd) is a psychrophilic fungus whose genus is commonly found in soils of colder environments, including stable habitats such as caves and mines. The fungus causes the epizootic disease white-nose syndrome, which is responsible for the mortality of millions of bats (Chiroptera) in North America through disruption of the hibernation cycle and of gas/water exchange processes that take place across wing membranes. To understand pathogenicity and fungal ecology with the goal of intervention, cultivation of Pd is essential. However, previous research on the fungus does not provide defined culturing standards and has mainly been focused on nucleic acid-based detection methods which can be used to identify the presence, but not viability, of the fungus. In order to standardize cultivation practices in vitro, a pure culture of Pd was tested on a wide array of media types previously described in the literature at both full and half strength concentrations. The goal was to identify media type(s) that supported timely fungal growth of Pd with conidia development but also minimized growth of competing fungal isolates, resulting in the selection of potato dextrose agar and yeast peptone dextrose agar. Applying use of these media with a standard protocol to environmental swab sampling, in conjunction with nucleic acid-based detection methods, allows for increased accuracy of risk determination for this fungal pathogen. Consistency in analysis can improve regional based management and fungal diagnostic work going forward, giving researchers and wildlife managers a more comprehensive understanding of Pd, including the ecology, transmission, and effects on bat species in North America.