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Abstract BackgroundHost microbiomes may differ under the same environmental conditions and these differences may influence susceptibility to infection. Amphibians are ideal for comparing microbiomes in the context of disease defense because hundreds of species face infection with the skin-invading microbeBatrachochytrium dendrobatidis(Bd), and species richness of host communities, including their skin bacteria (bacteriome), may be exceptionally high. We conducted a landscape-scale Bd survey of six co-occurring amphibian species in Brazil’s Atlantic Forest. To test the bacteriome as a driver of differential Bd prevalence, we compared bacteriome composition and co-occurrence network structure among the six focal host species. ResultsIntensive sampling yielded divergent Bd prevalence in two ecologically similar terrestrial-breeding species, a group with historically low Bd resistance. Specifically, we detected the highest Bd prevalence inIschnocnema henseliibut no Bd detections inHaddadus binotatus.Haddadus binotatuscarried the highest bacteriome alpha and common core diversity, and a modular network partitioned by negative co-occurrences, characteristics associated with community stability and competitive interactions that could inhibit Bd colonization. ConclusionsOur findings suggest that community structure of the bacteriome might drive Bd resistance inH. binotatus, which could guide microbiome manipulation as a conservation strategy to protect diverse radiations of direct-developing species from Bd-induced population collapses.
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This content will become publicly available on April 24, 2026
Nutrient enrichment alters the microbiome and increases chytrid load in the American bullfrog Lithobates catesbeianus
Agricultural practices have a profound impact on watershed dynamics, water quality, and the well-being of aquatic life. One major concern is agricultural pollution, particularly the excess of nutrients, which can elevate disease risks in various host-pathogen relationships. However, the exact mechanisms driving this effect remain uncertain. Elevated nutrient levels are believed to significantly influence populations of aquatic environmental bacteria, potentially reshaping the microbiomes of aquatic organisms and affecting their vulnerability to disease. Despite this, the impact of nutrient enrichment on host microbiomes as a link to diseases in aquatic organisms has been largely overlooked. In this study, we investigated the impact of nutrient enrichment on the skin-associated microbial communities of the American bullfrogLithobates catesbeianus. We observed a significant shift in bacterial richness and community composition in nutrient-enriched ponds compared with reference ponds. Although the proportion of the community inhibitory towardsBatrachochytrium dendrobatidis(Bd) did not change significantly,Bdloads were markedly higher in nutrient-enriched ponds. Nutrient enrichment significantly altered carbon utilization patterns as measured by Biolog EcoPlates, and antibiotic resistance was prevalent across all ponds and samples, with resistance to trimethoprim, sulfamethazine, and chloramphenicol significantly higher in nutrient-enriched ponds. Our findings indicate that nutrient enrichment affects the structure and function of skin-associated microbial communities in American bullfrogs, influencing bothBdload and antibiotic resistance.
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- Award ID(s):
- 2120084
- PAR ID:
- 10594520
- Publisher / Repository:
- Inter-Research
- Date Published:
- Journal Name:
- Diseases of Aquatic Organisms
- Volume:
- 162
- ISSN:
- 0177-5103
- Page Range / eLocation ID:
- 27 to 34
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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