The cutaneous microbiota of bats has in vitro antifungal activity against the white nose pathogen

2020 ◽  
Vol 96 (2) ◽  
Author(s):  
Matthew Grisnik ◽  
Olivia Bowers ◽  
Andrew J Moore ◽  
Benjamin F Jones ◽  
Joshua R Campbell ◽  
...  

ABSTRACT Since its introduction into the USA, Pseudogymnoascus destructans (Pd), the fungal pathogen of white-nose syndrome, has killed millions of bats. Recently, bacteria capable of inhibiting the growth of Pd have been identified within bat microbial assemblages, leading to increased interest in elucidating bacterial assemblage-pathogen interactions. Our objectives were to determine if bat cutaneous bacteria have antifungal activity against Pd, and correlate differences in the bat cutaneous microbiota with the presence/absence of Pd. We hypothesized that the cutaneous microbiota of bats is enriched with antifungal bacteria, and that the skin assemblage will correlate with Pd status. To test this, we sampled bat microbiota, adjacent roost surfaces and soil from Pd positive caves to infer possible overlap of antifungal taxa, we tested these bacteria for bioactivity in vitro, and lastly compared bacterial assemblages using both amplicon and shotgun high-throughput DNA sequencing. Results suggest that the presence of Pd has an inconsistent influence on the bat cutaneous microbial assemblage across sites. Operational taxonomic units (OTUs) that corresponded with cultured antifungal bacteria were present within all sample types but were significantly more abundant on bat skin relative to the environment. Additionally, the microbial assemblage of Pd negative bats was found to have more OTUs that corresponded to antifungal taxa than positive bats, suggesting an interaction between the fungal pathogen and cutaneous microbial assemblage.

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Kevin P. Drees ◽  
Jeffrey M. Lorch ◽  
Sebastien J. Puechmaille ◽  
Katy L. Parise ◽  
Gudrun Wibbelt ◽  
...  

ABSTRACT Globalization has facilitated the worldwide movement and introduction of pathogens, but epizoological reconstructions of these invasions are often hindered by limited sampling and insufficient genetic resolution among isolates. Pseudogymnoascus destructans , a fungal pathogen causing the epizootic of white-nose syndrome in North American bats, has exhibited few genetic polymorphisms in previous studies, presenting challenges for both epizoological tracking of the spread of this fungus and for determining its evolutionary history. We used single nucleotide polymorphisms (SNPs) from whole-genome sequencing and microsatellites to construct high-resolution phylogenies of P. destructans . Shallow genetic diversity and the lack of geographic structuring among North American isolates support a recent introduction followed by expansion via clonal reproduction across the epizootic zone. Moreover, the genetic relationships of isolates within North America suggest widespread mixing and long-distance movement of the fungus. Genetic diversity among isolates of P. destructans from Europe was substantially higher than in those from North America. However, genetic distance between the North American isolates and any given European isolate was similar to the distance between the individual European isolates. In contrast, the isolates we examined from Asia were highly divergent from both European and North American isolates. Although the definitive source for introduction of the North American population has not been conclusively identified, our data support the origin of the North American invasion by P. destructans from Europe rather than Asia. IMPORTANCE This phylogenetic study of the bat white-nose syndrome agent, P. destructans , uses genomics to elucidate evolutionary relationships among populations of the fungal pathogen to understand the epizoology of this biological invasion. We analyze hypervariable and abundant genetic characters (microsatellites and genomic SNPs, respectively) to reveal previously uncharacterized diversity among populations of the pathogen from North America and Eurasia. We present new evidence supporting recent introduction of the fungus to North America from a diverse Eurasian population, with limited increase in genetic variation in North America since that introduction.


2019 ◽  
Author(s):  
Hui Li ◽  
Siva L. S. Velivelli ◽  
Dilip M. Shah

AbstractAntimicrobial peptides play a pivotal role in the innate immunity of plants. Defensins are cysteine-rich antifungal peptides with multiple mechanisms of action (MOA). A novel Oleaceae-specific defensin gene family was discovered in the genome sequences of the wild and cultivated species of a perennial olive tree, Olea europaea. Antifungal properties of an olive tree defensin OefDef1.1 were investigated against a necrotrophic ascomycete fungal pathogen Botrytis cinerea in vitro and in planta. OefDef1.1 displayed potent antifungal activity against this pathogen by rapidly permeabilizing the plasma membrane of the conidial and germling cells. Interestingly, it was translocated to the cytoplasm and induced reactive oxygen species in the germlings, but not in the conidia. In medium containing high concentrations of Na1+, antifungal activity of OefDef1.1 against B. cinerea was significantly reduced. In contrast, OefDef1.1_V1 variant in which the γ-core motif of OefDef1.1 was replaced by that of a Medicago truncatula defensin MtDef4 displayed Na1+-tolerant antifungal activity and was more potent in reducing the virulence of B. cinerea in planta. OefDef1.1 also exhibited potent antifungal activity against three hemibiotrophic ascomycete pathogens Fusarium graminearum, F. oxysporum and F. virguliforme. Significant differences were observed among the four pathogens in their responses to OefDef1.1 in growth medium with or without the high concentrations of Na1+. The varied responses of closely related ascomycete pathogens to this defensin have implications for engineering disease resistance in plants.


2017 ◽  
Vol 372 (1712) ◽  
pp. 20160044 ◽  
Author(s):  
Kate E. Langwig ◽  
Joseph R. Hoyt ◽  
Katy L. Parise ◽  
Winifred F. Frick ◽  
Jeffrey T. Foster ◽  
...  

Increases in anthropogenic movement have led to a rise in pathogen introductions and the emergence of infectious diseases in naive host communities worldwide. We combined empirical data and mathematical models to examine changes in disease dynamics in little brown bat ( Myotis lucifugus ) populations following the introduction of the emerging fungal pathogen Pseudogymnoascus destructans , which causes the disease white-nose syndrome. We found that infection intensity was much lower in persisting populations than in declining populations where the fungus has recently invaded. Fitted models indicate that this is most consistent with a reduction in the growth rate of the pathogen when fungal loads become high. The data are inconsistent with the evolution of tolerance or an overall reduced pathogen growth rate that might be caused by environmental factors. The existence of resistance in some persisting populations of little brown bats offers a glimmer of hope that a precipitously declining species will persist in the face of this deadly pathogen. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’.


2016 ◽  
Vol 4 (3) ◽  
Author(s):  
Kevin P. Drees ◽  
Jonathan M. Palmer ◽  
Robert Sebra ◽  
Jeffrey M. Lorch ◽  
Cynthia Chen ◽  
...  

White-nose syndrome has recently emerged as one of the most devastating wildlife diseases recorded, causing widespread mortality in numerous bat species throughout eastern North America. Here, we present an improved reference genome of the fungal pathogen Pseudogymnoascus destructans for use in comparative genomic studies.


2020 ◽  
Vol 66 (10) ◽  
pp. 593-599
Author(s):  
Emma W. Micalizzi ◽  
Myron L. Smith

Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome, has killed millions of bats across eastern North America and continues to threaten new bat populations. The spread and persistence of P. destructans has likely been worsened by the ability of this fungus to grow as a saprotroph in the hibernaculum environment. Reducing the environmental growth of P. destructans may improve bat survival. Volatile organic compounds (VOCs) are attractive candidates to target environmental P. destructans, as they can permeate through textured environments that may be difficult to thoroughly contact with other control mechanisms. We tested in hibernaculum sediment the performance of VOCs that were previously shown to inhibit P. destructans growth in agar cultures and examined the inhibition kinetics and specificity of these compounds. Three VOCs, 2-methyl-1-butanol, 2-methyl-1-propanol, and 1-pentanol, were fungicidal towards P. destructans in hibernaculum sediment, fast-acting, and had greater effects against P. destructans than other Pseudogymnoascus species. Our results suggest that use of these VOCs may be considered further as an effective management strategy to reduce the environmental exposure of bats to P. destructans in hibernacula.


2020 ◽  
Author(s):  
Kate E. Langwig ◽  
J. Paul White ◽  
Katy L. Parise ◽  
Heather M. Kaarakka ◽  
Jennifer A. Redell ◽  
...  

AbstractEmerging infectious diseases can have devastating effects on host communities, causing population collapse and species extinctions. The timing of novel pathogen arrival into naïve species communities can have consequential effects that shape the trajectory of epidemics through populations. Pathogen introductions are often presumed to occur when hosts are highly mobile. However, spread patterns can be influenced by a multitude of other factors including host body condition and infectiousness.White-nose syndrome (WNS) is a seasonal emerging infectious disease of bats, which is caused by the fungal pathogen Pseudogymnoascus destructans. Within-site transmission of P. destructans primarily occurs over winter, however the influence of bat mobility and infectiousness on the seasonal timing of pathogen spread to new populations is unknown. We combined data on host population dynamics and pathogen transmission from 22 bat communities to investigate the timing of pathogen arrival and the consequences of varying pathogen arrival times on disease impacts.We found that midwinter arrival of the fungus predominated spread patterns, suggesting that bats were most likely to spread P. destructans when they are highly infectious, but have reduced mobility. In communities where P. destructans was detected in early winter, one species suffered higher fungal burdens and experienced more severe declines than at sites where the pathogen was detected later in the winter, suggesting that the timing of pathogen introduction had consequential effects for some bat communities. We also found evidence of source-sink population dynamics over winter, suggesting some movement among sites occurs during hibernation, even though bats at northern latitudes were thought to be fairly immobile during this period. Winter emergence behavior symptomatic of white-nose syndrome may further exacerbate these winter bat movements to uninfected areas.Our results suggest that low infectiousness during host migration may have reduced the rate of expansion of this deadly pathogen, and that elevated infectiousness during winter plays a key role in seasonal transmission. Furthermore, our results highlight the importance of both accurate estimation of the timing of pathogen spread and the consequences of varying arrival times to prevent and mitigate the effects of infectious diseases.


2018 ◽  
Author(s):  
Chapman Beekman ◽  
Lauren Meckler ◽  
Eleanor Kim ◽  
Richard J. Bennett

AbstractPseudogymnoascus destructans is the fungal pathogen responsible for White-nose Syndrome (WNS), a disease that has killed millions of bats in North America over the last decade. A major obstacle to research on P. destructans has been the lack of a tractable infection model for monitoring virulence. Here, we establish a high-throughput model of infection using larvae of Galleria mellonella, an invertebrate used to study host-pathogen interactions for a wide range of microbial species. We demonstrate that P. destructans can kill G. mellonella larvae in an inoculum-dependent manner when infected larvae are housed at 13°C or 18°C. Larval killing is an active process, as heat-killed P. destructans spores caused significantly decreased levels of larval death compared to live spores. We also show that fungal spores that were germinated prior to inoculation were able to kill larvae 3–4 times faster than non-germinated spores. Lastly, we identified chemical inhibitors of P. destructans and used G. mellonella to evaluate these inhibitors for their ability to reduce virulence. We demonstrate that two chemicals, trifluoperazine and amphotericin B, can effectively block larval killing by P. destructans and thereby establish that this infection model can be used to screen biocontrol agents against this fungal pathogen.


2016 ◽  
Vol 83 (5) ◽  
Author(s):  
Paris S. Hamm ◽  
Nicole A. Caimi ◽  
Diana E. Northup ◽  
Ernest W. Valdez ◽  
Debbie C. Buecher ◽  
...  

ABSTRACT At least two-thirds of commercial antibiotics today are derived from Actinobacteria, more specifically from the genus Streptomyces. Antibiotic resistance and new emerging diseases pose great challenges in the field of microbiology. Cave systems, in which actinobacteria are ubiquitous and abundant, represent new opportunities for the discovery of novel bacterial species and the study of their interactions with emergent pathogens. White-nose syndrome is an invasive bat disease caused by the fungus Pseudogymnoascus destructans, which has killed more than six million bats in the last 7 years. In this study, we isolated naturally occurring actinobacteria from white-nose syndrome (WNS)-free bats from five cave systems and surface locations in the vicinity in New Mexico and Arizona, USA. We sequenced the 16S rRNA region and tested 632 isolates from 12 different bat species using a bilayer plate method to evaluate antifungal activity. Thirty-six actinobacteria inhibited or stopped the growth of P. destructans, with 32 (88.9%) actinobacteria belonging to the genus Streptomyces. Isolates in the genera Rhodococcus, Streptosporangium, Luteipulveratus, and Nocardiopsis also showed inhibition. Twenty-five of the isolates with antifungal activity against P. destructans represent 15 novel Streptomyces spp. based on multilocus sequence analysis. Our results suggest that bats in western North America caves possess novel bacterial microbiota with the potential to inhibit P. destructans. IMPORTANCE This study reports the largest collection of actinobacteria from bats with activity against Pseudogymnoascus destructans, the fungal causative agent of white-nose syndrome. Using multigene analysis, we discovered 15 potential novel species. This research demonstrates that bats and caves may serve as a rich reservoir for novel Streptomyces species with antimicrobial bioactive compounds.


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