scholarly journals Probiotic treatment restores protection against lethal fungal infection lost during amphibian captivity

2016 ◽  
Vol 283 (1839) ◽  
pp. 20161553 ◽  
Author(s):  
Jordan G. Kueneman ◽  
Douglas C. Woodhams ◽  
Reid Harris ◽  
Holly M. Archer ◽  
Rob Knight ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Life Stage ◽  
Skin Microbiome ◽  
Janthinobacterium Lividum ◽  
Probiotic Treatment ◽  
In Captivity ◽  
Boreal Toads ◽  
Inhibitory Bacteria

Host-associated microbiomes perform many beneficial functions including resisting pathogens and training the immune system. Here, we show that amphibians developing in captivity lose substantial skin bacterial diversity, primarily due to reduced ongoing input from environmental sources. We combined studies of wild and captive amphibians with a database of over 1 000 strains that allows us to examine antifungal function of the skin microbiome. We tracked skin bacterial communities of 62 endangered boreal toads, Anaxyrus boreas , across 18 time points, four probiotic treatments, and two exposures to the lethal fungal pathogen Batrachochytrium dendrobatidis ( Bd ) in captivity, and compared these to 33 samples collected from wild populations at the same life stage. As the amphibians in captivity lost the Bd -inhibitory bacteria through time, the proportion of individuals exposed to Bd that became infected rose from 33% to 100% in subsequent exposures. Inoculations of the Bd -inhibitory probiotic Janthinobacterium lividum resulted in a 40% increase in survival during the second Bd challenge, indicating that the effect of microbiome depletion was reversible by restoring Bd -inhibitory bacteria. Taken together, this study highlights the functional role of ongoing environmental inputs of skin-associated bacteria in mitigating a devastating amphibian pathogen, and that long-term captivity decreases this defensive function.

scholarly journals Composition of symbiotic bacteria predicts survival in Panamanian golden frogs infected with a lethal fungus

2015 ◽  
Vol 282 (1805) ◽  
pp. 20142881 ◽  
Author(s):  
Matthew H. Becker ◽  
Jenifer B. Walke ◽  
Shawna Cikanek ◽  
Anna E. Savage ◽  
Nichole Mattheus ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Population Declines ◽  
Amphibian Species ◽  
Amphibian Population ◽  
New Approach ◽  
Skin Bacteria ◽  
Probiotic Treatment ◽  
Host Health ◽  
The Face ◽  
Inhibitory Bacteria

Symbiotic microbes can dramatically impact host health and fitness, and recent research in a diversity of systems suggests that different symbiont community structures may result in distinct outcomes for the host. In amphibians, some symbiotic skin bacteria produce metabolites that inhibit the growth of Batrachochytrium dendrobatidis (Bd), a cutaneous fungal pathogen that has caused many amphibian population declines and extinctions. Treatment with beneficial bacteria (probiotics) prevents Bd infection in some amphibian species and creates optimism for conservation of species that are highly susceptible to chytridiomycosis, the disease caused by Bd. In a laboratory experiment, we used Bd-inhibitory bacteria from Bd-tolerant Panamanian amphibians in a probiotic development trial with Panamanian golden frogs, Atelopus zeteki , a species currently surviving only in captive assurance colonies. Approximately 30% of infected golden frogs survived Bd exposure by either clearing infection or maintaining low Bd loads, but this was not associated with probiotic treatment. Survival was instead related to initial composition of the skin bacterial community and metabolites present on the skin. These results suggest a strong link between the structure of these symbiotic microbial communities and amphibian host health in the face of Bd exposure and also suggest a new approach for developing amphibian probiotics.

scholarly journals Seasonal and ontogenetic variation of skin microbial communities and relationships to natural disease dynamics in declining amphibians

2015 ◽  
Vol 2 (7) ◽  
pp. 140377 ◽  
Author(s):  
Ana V. Longo ◽  
Anna E. Savage ◽  
Ian Hewson ◽  
Kelly R. Zamudio
Keyword(s):  
Bacterial Diversity ◽  
Batrachochytrium Dendrobatidis ◽  
Developmental Stages ◽  
Pathogenic Fungus ◽  
Natural Populations ◽  
Amplicon Sequencing ◽  
Protective Role ◽  
Skin Microbiome ◽  
Skin Bacteria

Recently, microbiologists have focused on characterizing the probiotic role of skin bacteria for amphibians threatened by the fungal disease chytridiomycosis. However, the specific characteristics of microbial diversity required to maintain health or trigger disease are still not well understood in natural populations. We hypothesized that seasonal and developmental transitions affecting susceptibility to chytridiomycosis could also alter the stability of microbial assemblages. To test our hypothesis, we examined patterns of skin bacterial diversity in two species of declining amphibians ( Lithobates yavapaiensis and Eleutherodactylus coqui ) affected by the pathogenic fungus Batrachochytrium dendrobatidis ( Bd ). We focused on two important transitions that affect Bd susceptibility: ontogenetic (from juvenile to adult) shifts in E. coqui and seasonal (from summer to winter) shifts in  L. yavapaiensis . We used a combination of community-fingerprinting analyses and 16S rRNA amplicon sequencing to quantify changes in bacterial diversity and assemblage composition between seasons and developmental stages, and to investigate the relationship between bacterial diversity and pathogen load. We found that winter-sampled frogs and juveniles, two states associated with increased Bd susceptibility, exhibited higher diversity compared with summer-sampled frogs and adult individuals. Our findings also revealed that hosts harbouring higher bacterial diversity carried lower Bd infections, providing support for the protective role of bacterial communities. Ongoing work to understand skin microbiome resilience after pathogen disturbance has the potential to identify key taxa involved in disease resistance.

scholarly journals The Fungicide Chlorothalonil Changes the Amphibian Skin Microbiome: A Potential Factor Disrupting a Host Disease-Protective Trait

2021 ◽  
Vol 1 (1) ◽  
pp. 26-37
Author(s):  
Randall R. Jiménez ◽  
Gilbert Alvarado ◽  
Clemens Ruepert ◽  
Erick Ballestero ◽  
Simone Sommer
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Bacterial Community Composition ◽  
Model Organism ◽  
Amplicon Sequencing ◽  
Anthropogenic Factors ◽  
Skin Microbiome ◽  
Amphibian Skin ◽  
16S Rrna Amplicon Sequencing ◽  
Potential Factor ◽  
Inhibitory Bacteria

The skin microbiome is an important part of amphibian immune defenses and protects against pathogens such as the chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis. Alteration of the microbiome by anthropogenic factors, like pesticides, can impact this protective trait, disrupting its functionality. Chlorothalonil is a widely used fungicide that has been recognized as having an impact on amphibians, but so far, no studies have investigated its effects on amphibian microbial communities. In the present study, we used the amphibian Lithobates vibicarius from the montane forest of Costa Rica, which now appears to persist despite ongoing Bd-exposure, as an experimental model organism. We used 16S rRNA amplicon sequencing to investigate the effect of chlorothalonil on tadpoles’ skin microbiome. We found that exposure to chlorothalonil changes bacterial community composition, with more significant changes at a higher concentration. We also found that a larger number of bacteria were reduced on tadpoles’ skin when exposed to the higher concentration of chlorothalonil. We detected four presumed Bd-inhibitory bacteria being suppressed on tadpoles exposed to the fungicide. Our results suggest that exposure to a widely used fungicide could be impacting host-associated bacterial communities, potentially disrupting an amphibian protective trait against pathogens.

scholarly journals Bacterial Community in the Skin Microbiome of Frogs in a Coldspot of Chytridiomycosis Infection

2021 ◽  
Author(s):  
Milind C. Mutnale ◽  
Gundlapally S. Reddy ◽  
Karthikeyan Vasudevan
Keyword(s):  
Bacterial Community ◽  
Relative Abundance ◽  
Frog Skin ◽  
Batrachochytrium Dendrobatidis ◽  
Bacterial Community Composition ◽  
Skin Microbiome ◽  
Bacterial Phyla ◽  
Frog Species ◽  
Generation Sequencing

AbstractChytridiomycosis is a fungal disease caused by the pathogens, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), which has caused declines in amphibian populations worldwide. Asia is considered as a coldspot of infection, since adult frogs are less susceptible to Bd-induced mortality or morbidity. Using the next-generation sequencing approach, we assessed the cutaneous bacterial community composition and presence of anti-Bd bacteria in six frog species from India using DNA isolated from skin swabs. All the six frog species sampled were tested using nested PCR and found Bd negative. We found a total of 551 OTUs on frog skin, of which the bacterial phyla such as Proteobacteria (56.15% average relative abundance) was dominated followed by Actinobacteria (21.98% average relative abundance) and Firmicutes (13.7% average relative abundance). The contribution of Proteobacteria in the anti-Bd community was highest and represented by 175 OTUs. Overall, the anti-Bd bacterial community dominated (51.7% anti-Bd OTUs) the skin microbiome of the frogs. The study highlights the putative role of frog skin microbiome in affording resistance to Bd infections in coldspots of infection.

scholarly journals Fighting fungi with fungi: the mycobiome contribution to emerging disease in amphibians

2017 ◽  
Author(s):  
Patrick Kearns ◽  
Sarah Fischer ◽  
Saioa Fernández-Beaskoetxea ◽  
Caitlin Gabor ◽  
Jaime Bosch ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
High Throughput Sequencing ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Diseases ◽  
Pathogen Defense ◽  
Colonization Potential ◽  
Additional Resistance ◽  
Symbiotic Fungi

Emerging infectious diseases caused by fungal taxa are increasing and are placing a substantial burden on economies and ecosystems worldwide. Of the emerging fungal diseases, chytridomycosis caused by the fungus Batrachochytrium dendrobatidis (hereafter Bd) is causing a global amphibian extinction. The host frog does have come internal innate immunity, as well as additional resistance through cutaneous microbial communities, leading to the development of probiotic bacterial therapies with mixed results. Unknown is the role of fungi in the protection against Bd infection, and as such, we examined the overlapping roles of bacterial and fungal microbiota in pathogen defense with a combination of high-throughput sequencing and culturing of symbiotic fungi from poison arrow frogs (Dendrobates sp.). Our analyses revealed that abundance of cutaneous fungi contributed more to pathogen defense (~45%), than bacteria (~10%) and these differed from environmental microbiota. Further, we demonstrated that a fungal probiotic therapy did not induce an endocrine-immune reaction in contrast to bacterial probiotics that stressed amphibian hosts and suppressed antimicrobial peptide responses, limiting their long-term colonization potential. Our results suggest that probiotic strategies against amphibian fungal pathogens should refocus on host-associated and environmental fungi such as Penicillium and member of the families Chaetomiaceae and Lasiosphaeriaceae.

scholarly journals The Role of Every-Day Cosmetics in Altering the Skin Microbiome: A Study Using Biodiversity

Cosmetics ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 2 ◽  
Author(s):  
Christopher Wallen-Russell
Keyword(s):  
Independent Study ◽  
Skin Microbiome ◽  
Rrna Sequencing ◽  
Human Participants ◽  
Medical University ◽  
First Time ◽  
Larger Sample ◽  
Universal Standard

As described in previous work, the use of synthetic chemical ingredients in modern cosmetics is postulated to be a cause of damage to the skin microbiome. The discovery that biodiversity on the human skin is currently the only reliable indicator of skin health, meant that for the first time, a mechanism to test for healthy skin was possible. Using this mechanism and in collaboration with The Medical University of Graz, who carried out the independent study, this work aimed to help answer whether modern day synthetic cosmetics are a main cause of long-term damage to the skin microbiome. Thirty-two human participants tested three different face washes for their effect on the skin’s microbial diversity, along with skin pH, moisture and TEWL (trans-epidermal water loss), washing twice-a-day for four weeks. The upper volar forearm of the volunteers was swabbed at the beginning, two weeks in and at the end of the four weeks. 16S rRNA sequencing was used. One leading ‘natural’ brand full of synthetic ingredients, a leading synthetic brand and a 100% natural face wash were used. Results give the first indications of a link between synthetic ingredients in a cosmetics product and its effect on skin microbiome biodiversity. It paves the way for future studies on the topic with a larger sample group, longer test period and standardised methodology to create a universal standard for testing the health of skin using benchmark diversity values. This can be used in the future to test the effectiveness of cosmetics or ingredients on skin health, leading to the restriction in cosmetics of products proven to harm the skin’s natural environment.

scholarly journals Fighting fungi with fungi: the mycobiome contribution to emerging disease in amphibians

2017 ◽  
Author(s):  
Patrick Kearns ◽  
Sarah Fischer ◽  
Saioa Fernández-Beaskoetxea ◽  
Caitlin Gabor ◽  
Jaime Bosch ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
High Throughput Sequencing ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Diseases ◽  
Pathogen Defense ◽  
Colonization Potential ◽  
Additional Resistance ◽  
Symbiotic Fungi

Emerging infectious diseases caused by fungal taxa are increasing and are placing a substantial burden on economies and ecosystems worldwide. Of the emerging fungal diseases, chytridomycosis caused by the fungus Batrachochytrium dendrobatidis (hereafter Bd) is causing a global amphibian extinction. The host frog does have come internal innate immunity, as well as additional resistance through cutaneous microbial communities, leading to the development of probiotic bacterial therapies with mixed results. Unknown is the role of fungi in the protection against Bd infection, and as such, we examined the overlapping roles of bacterial and fungal microbiota in pathogen defense with a combination of high-throughput sequencing and culturing of symbiotic fungi from poison arrow frogs (Dendrobates sp.). Our analyses revealed that abundance of cutaneous fungi contributed more to pathogen defense (~45%), than bacteria (~10%) and these differed from environmental microbiota. Further, we demonstrated that a fungal probiotic therapy did not induce an endocrine-immune reaction in contrast to bacterial probiotics that stressed amphibian hosts and suppressed antimicrobial peptide responses, limiting their long-term colonization potential. Our results suggest that probiotic strategies against amphibian fungal pathogens should refocus on host-associated and environmental fungi such as Penicillium and member of the families Chaetomiaceae and Lasiosphaeriaceae.

scholarly journals Assessing host extinction risk following exposure to Batrachochytrium dendrobatidis

2014 ◽  
Vol 281 (1785) ◽  
pp. 20132783 ◽  
Author(s):  
Stilianos Louca ◽  
Margarita Lampo ◽  
Michael Doebeli
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Extinction Risk ◽  
Life Stage ◽  
Adult Life ◽  
Host Population ◽  
Amphibian Conservation ◽  
Relevant Parameter ◽  
Wildlife Diseases ◽  
Host Extinction

Wildlife diseases are increasingly recognized as a major threat to biodiversity. Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungus Batrachochytrium dendrobatidis ( Bd ). Using a mathematical model and simulations, we study its effects on a generic riparian host population with a tadpole and adult life stage. An analytical expression for the basic reproduction quotient, Q o , of the pathogen is derived. By sampling the entire relevant parameter space, we perform a statistical assessment of the importance of all considered parameters in determining the risk of host extinction, upon exposure to Bd . We find that Q o not only gives a condition for the initial invasion of the fungus, but is in fact the best predictor for host extinction. We also show that the role of tadpoles, which in some species tolerate infections, is ambivalent. While tolerant tadpoles may provide a reservoir for the fungus, thus facilitating its persistence or even amplifying its outbreaks, they can also act as a rescue buffer for a stressed host population. Our results have important implications for amphibian conservation efforts.

scholarly journals The Role of Every-Day Cosmetics in Altering the Skin Microbiome: A Study Using Biodiversity

2018 ◽  
Author(s):  
Christopher Wallen-Russell
Keyword(s):  
Independent Study ◽  
Skin Microbiome ◽  
Rrna Sequencing ◽  
Human Participants ◽  
Medical University ◽  
First Time ◽  
Larger Sample ◽  
Universal Standard

As described in previous work, the use of synthetic chemical ingredients in modern cosmetics is postulated to be a cause of damage to the skin microbiome. The discovery that biodiversity on the human skin is currently the only reliable indicator of skin health, meant that for the first time, a mechanism to test for healthy skin was possible. Using this mechanism and in collaboration with The Medical University of Graz, who carried out the independent study, this work aimed to help answer whether modern day synthetic cosmetics are a main cause of long term damage to the skin microbiome. Thirty-two human participants tested three different face washes for their effect on the skin’s microbial diversity, along with skin pH, moisture and TEWL (trans-epidermal water loss), washing twice a day for four weeks. The upper volar forearm of the volunteers was swabbed at the beginning, two weeks in and end (four weeks). 16S rRNA sequencing was used. One leading ‘natural’ brand full of synthetic ingredients, a leading synthetic brand and a 100% natural face wash were used. Results give the first indications of a link between synthetic ingredients in a cosmetics product, and its effect on skin microbiome biodiversity. It paves the way for future studies on the topic with a larger sample group, longer test period and standardised methodology to create a universal standard for testing the health of skin using benchmark diversity values. This can be used in the future to test the effectiveness of cosmetics or ingredients on skin health, leading to the banning of products proven to harm the skin’s natural environment.

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