Analysis and Exploration of Novel Antibiotic-Producing Streptomyces spp. in Spokane County, Washington

According to the Centers for Disease Control and Prevention, a US citizen is infected by an antibiotic-resistant pathogen every 11 seconds, and every 15 minutes, a patient dies as a result of these infections. Due to the increasing incidence of antibiotic-resistant pathogenic microbes, the study and exploration of novel antibiotics from novel environments are imperative as infectious diseases are the second leading cause of death in the United States. The purpose of this research is to investigate and analyze antibiotic-producing soil microbes in Spokane County, WA, with hopes of discovering novel antibiotic-producing microbes, specifically Streptomyces species, and explore some of the variables that influence the production of secondary metabolites. My hypotheses are as follows: Soil microbes existing in Spokane County will include Streptomyces spp. capable of producing secondary metabolites suitable to combat selected Gram-negative or Gram-positive bacterial ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) and pathogenic fungi such as Candida albicans. Additionally, modifying laboratory variables such as incubation temperature, time in incubation, and the type of media will influence the production of metabolites produced by Streptomyces isolates. Modifying these variables will impact the inhibitory capabilities of these isolates against Gram-negative, Gram-positive, and pathogenic fungal microbes. Cell-free supernatants of secondary metabolites on disk diffusion and 96 well plate assays will be utilized to measure zones of inhibition and inhibitory capabilities with absorbance measured at 600nm using a spectrophotometer

Preparing for a Bsal invasion into North America has improved multi-sector readiness

Western palearctic salamander susceptibility to the skin disease caused by the amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) was recognized in 2014, eliciting concerns for a potential novel wave of amphibian declines following the B. dendrobatidis (Bd) chytridiomycosis global pandemic. Although Bsal had not been detected in North America, initial experimental trials supported the heightened susceptibility of caudate amphibians to Bsal chytridiomycosis, recognizing the critical threat this pathogen poses to the North American salamander biodiversity hotspot. Here, we take stock of 10 years of research, collaboration, engagement, and outreach by the North American Bsal Task Force. We summarize main knowledge and conservation actions to both forestall and respond to Bsal invasion into North America. We address the questions: what have we learned; what are current challenges; and are we ready for a more effective reaction to Bsal’s eventual detection? We expect that the many contributions to preemptive planning accrued over the past decade will pay dividends in amphibian conservation effectiveness and can inform future responses to other novel wildlife diseases and extreme threats

Genetic variability and ontogeny predict microbiome structure in a disease-challenged montane amphibian

Amphibian populations worldwide are at risk of extinction from infectious diseases, including chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Amphibian cutaneous microbiomes interact with Bd and can confer protective benefits to the host. The composition of the microbiome itself is influenced by many environment- and host-related factors. However, little is known about the interacting effects of host population structure, genetic variation and developmental stage on microbiome composition and Bd prevalence across multiple sites. Here we explore these questions in Amietia hymenopus, a disease-affected frog in southern Africa. We use microsatellite genotyping and 16S amplicon sequencing to show that the microbiome associated with tadpole mouthparts is structured spatially, and is influenced by host genotype and developmental stage. We observed strong genetic structure in host populations based on rivers and geographic distances, but this did not correspond to spatial patterns in microbiome composition. These results indicate that demographic and host genetic factors affect microbiome composition within sites, but different factors are responsible for host population structure and microbiome structure at the between-site level. Our results help to elucidate complex within- and among- population drivers of microbiome structure in amphibian populations. That there is a genetic basis to microbiome composition in amphibians could help to inform amphibian conservation efforts against infectious diseases

Antifungal isolates database of amphibian skin-associated bacteria and function against emerging fungal pathogens

Microbial symbionts of vertebrate skin have an important function in defense of the host against pathogens. In particular, the emerging chytrid fungus Batrachochytrium dendrobatidis, causes widespread disease in amphibians but can be inhibited via secondary metabolites produced by many different skin-associated bacteria. Similarly, the fungal pathogens of terrestrial salamander eggs Mariannaea elegans and Rhizomucor variabilis are also inhibited by a variety of skin-associated bacteria. Indeed, probiotic therapy against fungal diseases is a recent approach in conservation medicine with growing experimental support. We present a comprehensive Antifungal Isolates Database of amphibian skin-associated bacteria that have been cultured, isolated, and tested for antifungal properties. At the start, this database includes nearly 2000 cultured bacterial isolates from 37 amphibian host species across 18 studies on five continents: Africa, Oceania, Europe, and North and South America. As the research community gathers information on additional isolates, the database will be updated periodically. The resulting database can serve as a conservation tool for amphibians and other organisms, and provides empirical data for comparative and bioinformatic studies. The database consists of a FASTA file containing 16S rRNA gene sequences of the bacterial isolates, and a metadata file containing information on the host species, life-stage, geographic region, and antifungal capacity and taxonomic identity of the isolate

Impact of Chytrid Fungus Pathogen on Skin Microbiome of Columbia Spotted Frogs in Northern Idaho

Chytridiomycosis, an emerging infectious disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is associated with an estimated 501 population declines and 90 extinctions of amphibian species worldwide, the greatest documented loss of biodiversity attributed to a disease. Research on the amphibian skin microbiome may provide solutions to conservation of amphibian species by bettering our understanding of 1) Bd’s effect on the skin’s microbial community composition and 2) the effects of microbial community composition in protection against Bd. Our goal was to investigate differences in microbiome composition between infected and uninfected frogs. DNA samples from skins of 399 Columbia spotted frogs (Rana luteiventris) were obtained by the Idaho Department of Fish and Game in 2013-2014. Frogs were sampled from a total of 153 wetlands in northern Idaho, with Bd being detected on frogs in 80% (123) of the sampled wetlands. Of the 399 spotted frogs tested for Bd presence, 65% (261 frogs) tested positive. The average infection intensity was low, with zoospore equivalents ranging from 0 to 98.8 (mean = 0.93). The skin microbiomes of 92 frogs (47 infected and 45 uninfected) were characterized using amplicon barcoded sequencing of the V4-V5 region of the 16S rRNA gene. Infected and uninfected frogs had distinct microbiomes (p = .024, pseudo-F = 2.07, PERMANOVA, weighted UniFrac). A member of the order Burkholderiales, known to dominate the microbiome of highly infected frogs, increased in relative abundance in infected frogs. Pseudomonas spp., a known inhibitor of Bd, had greater relative abundance in uninfected frogs, potentially improving defenses against the disease

Cloacal bacterial communities of tree swallows (Tachycineta bicolor): Similarity within a population, but not between pair-bonded social partners

Host-associated microbial communities can influence the overall health of their animal hosts, and many factors, including behavior and physiology, can impact the formation of these complex communities. Bacteria within these communities can be transmitted socially between individuals via indirect (e.g., shared environments) or direct (e.g., physical contact) pathways. Limited research has been done to investigate how social interactions that occur in the context of mating shape host-associated microbial communities. To gain a better understanding of these interactions and, more specifically, to assess how mating behavior shapes an animal’s microbiome, we studied the cloacal bacterial communities of a socially monogamous yet genetically polygynous songbird, the North American tree swallow (Tachycineta bicolor). We address two questions: (1) do the cloacal bacterial communities differ between female and male tree swallows within a population? and (2) do pair-bonded social partners exhibit more similar cloacal bacterial communities than expected by chance? To answer these questions, we sampled the cloacal microbiome of adults during the breeding season and then used culture-independent, 16S rRNA gene amplicon sequencing to assess bacterial communities. Overall, we found that the cloacal bacterial communities of females and males were similar, and that the communities of pair-bonded social partners were not more similar than expected by chance. Our results suggest that social monogamy does not correlate with an increased similarity in cloacal bacterial community diversity or structure. As social partners were not assessed at the same time, it is possible that breeding stage differences masked social effects on bacterial community diversity and structure. Further, given that tree swallows exhibit high variation in rates of extra-pair activity, considering extra-pair activity when assessing cloacal microbial communities may be important for understanding how these bacterial communities are shaped. Further insight into how bacterial communities are shaped will ultimately shed light on potential tradeoffs associated with alternative behavioral strategies and socially-transmitted microbes

Athlétic-tribune sportive : hebdomadaire illustré / [directeurs Roger Roujean, Pierre Pradeu]

26 octobre 19331933/10/26 (A15,N708)-1933/10/26.Appartient à l’ensemble documentaire : Aquit

Data from: Phylogenetic distribution of symbiotic bacteria from Panamanian amphibians that inhibit growth of the lethal fungal pathogen Batrachochytrium dendrobatidis

The introduction of next-generation sequencing has allowed for greater understanding of community composition of symbiotic microbial communities. However, determining the function of individual members of these microbial communities still largely relies on culture-based methods. Here, we present results on the phylogenetic distribution of a defensive functional trait of cultured symbiotic bacteria associated with amphibians. Amphibians are host to a diverse community of cutaneous bacteria and some of these bacteria protect their host from the lethal fungal pathogen Batrachochytrium dendrobatidis (Bd) by secreting antifungal metabolites. We cultured over 450 bacterial isolates from the skins of Panamanian amphibian species and tested their interactions with Bd using an in vitro challenge assay. For a subset of isolates, we also completed coculture experiments and found that culturing isolates with Bd had no effect on inhibitory properties of the bacteria, but it significantly decreased metabolite secretion. In challenge assays, approximately 75% of the bacterial isolates inhibited Bd to some extent and these inhibitory isolates were widely distributed among all bacterial phyla. Although there was no clear phylogenetic signal of inhibition, three genera, Stenotrophomonas, Aeromonas and Pseudomonas, had a high proportion of inhibitory isolates (100%, 77% and 73%, respectively). Overall, our results demonstrate that antifungal properties are phylogenetically widespread in symbiotic microbial communities of Panamanian amphibians and that some functional redundancy for fungal inhibition occurs in these communities. We hope that these findings contribute to the discovery and development of probiotics for amphibians that can mitigate the threat of chytridiomycosis

Bacterial Isolate data

This file includes information for each bacterial isolate assayed in the study. Isolate ID, 16s rRNA sequence, the source and site the isolate was collected from, mean Bd inhibition, and taxonomic identification are listed for each isolate