DNA-based detection of the fungal pathogen Geomyces destructans in soils from bat hibernacula

Abstract

White-nose syndrome (WNS) is an emerging disease causing unprecedented morbidity and mortality among bats in eastern North America. The disease is characterized by cutaneous infection of hibernating bats by the psychrophilic fungus Geomyces destructans. Detection of G. destructans in environments occupied by bats will be critical for WNS surveillance, management and characterization of the fungal lifecycle. We initiated an rRNA gene region-based molecular survey to characterize the distribution of G. destructans in soil samples collected from bat hibernacula in the eastern United States with an existing PCR test. Although this test did not specifically detect G. destructans in soil samples based on a presence/absence metric, it did favor amplification of DNA from putative Geomyces species. Cloning and sequencing of PCR products amplified from 24 soil samples revealed 74 unique sequence variants representing 12 clades. Clones with exact sequence matches to G. destructans were identified in three of 19 soil samples from hibernacula in states where WNS is known to occur. Geomyces destructans was not identified in an additional five samples collected outside the region where WNS has been documented. This study highlights the diversity of putative Geomyces spp. in soil from bat hibernacula and indicates that further research is needed to better define the taxonomy of this genus and to develop enhanced diagnostic tests for rapid and specific detection of G. destructans in environmental samples.

Psychrophilic and Psychrotolerant Fungi on Bats and the Presence of Geomyces spp. on Bat Wings Prior to the Arrival of White Nose Syndrome

“…These results showed very low resolution, but the tree topology is consistent with previously published phylogenies for this genus (15,24). The 11 Geomyces isolates from Illinois cluster into seven distinct clades, three of which are highly supported by BS and BPP.…”

“…In addition to the ITS sequences generated during this study, numerous other sequences from various Geomyces species were included in the analyses (13,15,(22)(23)(24)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56). The majority of Geomyces sequences included in the tree were derived from taxa found in soil under bat hibernacula in the northeastern United States (15).…”

“…This is of vital importance because bats may act as reservoirs of fungi that are opportunistic pathogens or biological control agents that may have a role in the spread or control of WNS (25). Previous studies documenting fungal diversity in caves have focused mostly on cave soil and bat guano (15,24,30,31) and rarely on the composition of mycobiomes on bats (32,33). The main goal of this study was to document the psychrophilic fungal community on bats prior to the arrival of WNS.…”

“…Geomyces species are cosmopolitan and have been isolated from cave deposits, bats, and soils of cold climates such as Antarctic soils, Artic cryopegs, submarine soils, and Canadian Sphagnum bogs (15,(20)(21)(22)(23)(24)(25). Geomyces destructans is considered a true psychrophile, with a growth temperature ranging from 3 to 20°C and no growth occurring at 24°C or higher (13,26,27).…”

Bat‐cave catchment areas: using stable isotopes (δD) to determine the probable origins of hibernating bats

“…WNS threatens all cavedwelling bat species in North America (Foley et al 2011). Human activity may translocate G. destructans (Linder et al 2011), but seasonal bat movements and interactions are thought to be the driving force behind the spread of the disease (Frick et al 2010, Hallam and McCracken 2010, Foley et al 2011. Quantifying the connectivity between summer roosts and winter hibernacula is essential to predict the spread of WNS.…”