Vaccine Against Deadly Chytrid Fungus Primes Frog Microbiome For Future Exposure
Published:28 Jun.2023 Source:Penn State
"The microorganisms that make up an animal's microbiome can often help defend against pathogens, for example by producing beneficial substances or by competing against the pathogens for space or nutrients," said Gui Becker, associate professor of biology at Penn State and leader of the research team. "But what happens to your microbiome when you get a vaccine, like a COVID vaccine, a flu shot, or a live-attenuated vaccine like the yellow fever vaccine? In this study, we used frogs as a model system to start exploring this question."
Frogs and other amphibians are threatened by the chytrid fungus, which has led to extinctions of some species and severe population declines in hundreds of others across several continents. In susceptible species, the fungus causes a sometimes-lethal skin disease.
"Chytrid is one of the worst, if not the worst, pathogen for wildlife conservation in recent history, and there is a critical need to develop tools to control its spread," said Becker, who is also a member of the One Health Microbiome Center and the Center for Infectious Disease Dynamics at Penn State. "We found that, in some cases, vaccines can induce a protective shift in the microbiome, which suggests that carefully manipulating the microbiome could be used as part of a broader strategy to help amphibians, and perhaps other vertebrates, deal with emerging pathogens."
The researchers applied a vaccine, in this case a non-lethal dosage of a metabolic product created by the chytrid fungus to tadpoles. After five weeks, they observed how the composition of the microbiome had changed, identifying individual species of bacteria and their relative proportions. The researchers also cultured each species of bacteria in the lab and tested whether bacteria-specific products facilitated, inhibited, or had no effect on chytrid growth, adding to and comparing results with a large database of this information.