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Pseudogymnoascus destructans (Pd) is the causative agent of white-nose syndrome, which has resulted in the death of millions of bats in North America (NA) since 2006. Based on mortalities in eastern NA, the westward spread of infections likely poses a significant threat to western NA bats. To help prevent/reduce Pd infections in bats in western NA, we isolated bacteria from the wings of wild bats and screened for inhibitory activity against Pd. In total, we obtained 1,362 bacterial isolates from 265 wild bats of 13 species in western Canada. Among the 1,362 isolates, 96 showed inhibitory activity against Pd based on a coculture assay. The inhibitory activities varied widely among these isolates, ranging from slowing fungal growth to complete inhibition. Interestingly, host bats containing isolates with anti-Pd activities were widely distributed, with no apparent geographic or species-specific pattern. However, characteristics of roosting sites and host demography showed significant associations with the isolation of anti-Pd bacteria. Specifically, anthropogenic roosts and swabs from young males had higher frequencies of anti-Pd bacteria than those from natural roosts and those from other sex and age-groups, respectively. These anti-Pd bacteria could be potentially used to help mitigate the impact of WNS. Field trials using these as well as additional microbes from future screenings are needed in order to determine their effectiveness for the prevention and treatment against WNS. [ABSTRACT FROM AUTHOR]

White-nose syndrome (WNS) is an ongoing epizootic affecting multiple species of North American bats, caused by epidermal infections of the psychrophilic filamentous fungus Pseudogymnoascus destructans Since its introduction from Europe, WNS has spread rapidly across eastern North America and resulted in high mortality rates in bats. At present, the mechanisms behind its spread and the extent of its adaptation to different geographic and ecological niches remain unknown. The objective of this study was to examine the geographic patterns of phenotypic variation and the potential evidence for adaptation among strains representing broad geographic locations in eastern North America. The morphological features of these strains were evaluated on artificial medium, and the viability of asexual arthroconidia of representative strains was investigated after storage at high (23°C), moderate (14°C), and low (4°C) temperatures at different lengths of time. Our analyses identified evidence for a geographic pattern of colony morphology changes among the clonal descendants of the fungus, with trait values correlated with increased distance from the epicenter of WNS. Our genomic comparisons of three representative isolates revealed novel genetic polymorphisms and suggested potential candidate mutations that might be related to some of the phenotypic changes. These results show that even though this pathogen arrived in North America only recently and reproduces asexually, there has been substantial evolution and phenotypic diversification during its rapid clonal expansion. IMPORTANCE The causal agent of white-nose syndrome in bats is Pseudogymnoascus destructans , a filamentous fungus recently introduced from its native range in Europe. Infections caused by P. destructans have progressed across the eastern parts of Canada and the United States over the last 10 years. It is not clear how the disease is spread, as the pathogen is unable to grow above 23°C and ambient temperature can act as a barrier when hosts disperse. Here, we explore the patterns of phenotypic diversity and the germination of the fungal asexual spores, arthroconidia, from strains across a sizeable area of the epizootic range. Our analyses revealed evidence of adaptation along geographic gradients during its expansion. The results have implications for understanding the diversification of P. destructans and the limits of WNS spread in North America. Given the rapidly expanding distribution of WNS, a detailed understanding of the genetic bases for phenotypic variations in growth, reproduction, and dispersal of P. destructans is urgently needed to help control this disease., (Copyright © 2018 American Society for Microbiology.)