Abstract
Batrachochytrium dendrobatidis (Bd) is an emerging fungal skin pathogen of amphibians that has affected frog and salamander populations across the globe. Some populations appear to tolerate Bd better than others, and there is evidence that bacteria of the amphibian skin microbiome may play a role in this phenomenon. The relationship between Bd and amphibians is not only an issue of great conservation significance, but studying it can shed light on host-pathogen interactions more generally, particularly the role microbes play in disease dynamics of wild organisms. In this study, skin swabs were collected from northern two-lined salamanders and analyzed for the presence of Bd using qPCR. Then, the microbiomes of Bd positive and Bd negative individuals were characterized using 16s v3-v4 metagenomic sequencing and compared.
Of the salamanders sampled in this study, 6.1% (n = 98) were positive for Bd. This study is the ninth year of sampling for Bd in this population, and, across all years, 13.6% of salamanders were positive for Bd (n = 704). Over the past nine years, there was a significantly higher frequency of Bd prevalence in 2020 and 2022. There were also significant differences in the frequency of Bd between creeks sampled over the past nine years.
Metagenomic sequencing revealed that various genera known to contain Bd-inhibiting species were present on all individuals sequenced (n = 15). One family of bacteria, Alcaligenaceae, was significantly more abundant on Bd negative salamanders (n = 8). One uncultured phylum, GAL15 (Sysuimicrobiota), was significantly more abundant on Bd positive salamanders (n = 7). These results suggest that Bd is in the enzootic phase of disease within our population, and that Bd-inhibiting bacteria are common both on Bd positive and negative salamanders.
Advisor
Lehtinen, Richard
Department
Biology
Recommended Citation
Wasielewski, Will, "Exploring the Relationship Between a Fungal Pathogen and the Skin Microbiome in Northern Two Lined Salamanders" (2025). Senior Independent Study Theses. Paper 11639.
https://openworks.wooster.edu/independentstudy/11639
Disciplines
Environmental Microbiology and Microbial Ecology | Evolution
Keywords
Batrachochytrium dendrobatidis, salamanders, microbiome
Publication Date
2025
Degree Granted
Bachelor of Arts
Document Type
Senior Independent Study Thesis
© Copyright 2025 Will Wasielewski