Morphological and Molecular Characterizations of Psychrophilic Fungus Geomyces destructans from New York Bats with White Nose Syndrome (WNS)

Abstract

BackgroundMassive die-offs of little brown bats (Myotis lucifugus) have been occurring since 2006 in hibernation sites around Albany, New York, and this problem has spread to other States in the Northeastern United States. White cottony fungal growth is seen on the snouts of affected animals, a prominent sign of White Nose Syndrome (WNS). A previous report described the involvement of the fungus Geomyces destructans in WNS, but an identical fungus was recently isolated in France from a bat that was evidently healthy. The fungus has been recovered sparsely despite plentiful availability of afflicted animals.Methodology/Principal FindingsWe have investigated 100 bat and environmental samples from eight affected sites in 2008. Our findings provide strong evidence for an etiologic role of G. destructans in bat WNS. (i) Direct smears from bat snouts, Periodic Acid Schiff-stained tissue sections from infected tissues, and scanning electron micrographs of bat tissues all showed fungal structures similar to those of G. destructans. (ii) G. destructans DNA was directly amplified from infected bat tissues, (iii) Isolations of G. destructans in cultures from infected bat tissues showed 100% DNA match with the fungus present in positive tissue samples. (iv) RAPD patterns for all G. destructans cultures isolated from two sites were indistinguishable. (v) The fungal isolates showed psychrophilic growth. (vi) We identified in vitro proteolytic activities suggestive of known fungal pathogenic traits in G. destructans.Conclusions/SignificanceFurther studies are needed to understand whether G. destructans WNS is a symptom or a trigger for bat mass mortality. The availability of well-characterized G. destructans strains should promote an understanding of bat–fungus relationships, and should aid in the screening of biological and chemical control agents.

Destructin-1 is a collagen-degrading endopeptidase secreted by Pseudogymnoascus destructans , the causative agent of white-nose syndrome

“…1A). The diversity of hydrolytic enzymes present is consistent with previous reports of multiple hydrolytic activities in P. destructans cultures, although the proteins responsible for these activities were not determined (21,22). Many of these enzymes are likely to play a role in saprophytic growth, but peptidases have also been identified in the secretomes of the human pathogens C. albicans and Aspergillus fumigatus (23,24), where they mediate host-pathogen interactions (14,15).…”

“…Connective tissue, vascular structures, and muscle fibers are degraded during infection, suggesting that hydrolytic enzymes are used by the invading pathogen (27). Secreted hydrolytic activities have been described by monitoring growth of P. destructans on a wide range of in vitro substrates (21,22), but the fungal proteins responsible for these activities have not been elucidated.…”

Galleria mellonella experimental model for bat fungal pathogen Pseudogymnoascus destructans and human fungal pathogen Pseudogymnoascus pannorum

“…Pseudogymnoascus destructans is the fungal causal agent of WNS [5]. Pseudogymnoascus destructans is a psychrophile, well-adapted to growing at 4°-15°C, and widely distributed in the caves and mines that serve as bat hibernacula [5–8]. Bats infected with P. destructans exhibit histopathological lesions on wings and other body parts, are frequently aroused from hibernation-induced torpor, and possibly succumb to WNS due to fat depletion and starvation [9–11].…”

Editorial: What is in a Name? A Proposal to Use Geomycosis Instead of White Nose Syndrome (WNS) to Describe Bat Infection Caused by Geomyces Destructans

“…Subsequent studies indicated that the cottony appearance was due to fungal growth. The extensive fungal colonization of bat skin and hair, characteristic histopathological appearance, and exclusive presence of a specific fungal DNA in the animals' tissues led to the discovery of the causal agent-a newly described species called Geomyces destructans [2][3][4][5][6]. Subsequent studies revealed that this condition has caused the deaths of nearly a million bats in the Northeast and it has rapidly spread to other parts of the country [7].…”

“…Accordingly, this disease can be confirmed by the morphological appearance of the fungus on any part of the body, histopathology of affected tissues with demonstration of hyphae-conidia, or demonstration of G. destructans by PCR-nucleotide sequencing [3,4,6,11]. Thus, it is reasonable to conclude that WNS is neither an exclusive presentation nor an all-encompassing description of G. destructans infections in bats.…”