Associations of Batrachochytrium dendrobatidis with skin bacteria and fungi on Asian amphibian hostsOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined how the fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes chytridiomycosis, associates with skin bacteria and fungi on Asian amphibians. Skin swabs were sequenced for bacterial 16S rRNA and fungal ITS2 genes. Researchers compared microbial diversity and composition by infection status and infection intensity, measured as Bd sequence reads. They also tracked putative anti-Bd bacteria and built co-occurrence networks for infected versus uninfected frogs.
Who was studied?
The study sampled 63 wild adult amphibians from four species in the high-altitude forests of Guangxi, southern China. The species included two stream-breeding and two pond-breeding taxa, all documented Bd hosts. Guangxi is a region of high Bd lineage diversity, and these hosts carried subclinical infections. Swabs were collected between April and May 2021, when pathogen prevalence is high. This was a field study of wild animals, not a laboratory or human cohort.
What were the most important findings?
Both skin bacterial and fungal communities were associated with Bd infection status and intensity. Infected frogs showed higher relative abundance of the phylum Proteobacteria and lower Bacteroidota (weighted Bray-Curtis PERMANOVA, p = 0.001). Fungal richness dropped in infected frogs, while bacterial richness correlated with infection intensity in two species. Researchers found 127 putative anti-Bd bacterial ASVs, of which 68 were shared across all four species. Anti-Bd bacterial richness tracked infection status and intensity. Co-occurrence networks of infected frogs had more keystone connector genera (19 versus 7), indicating stronger inter-module bacterial interactions.
What are the greatest implications of this study?
The results suggest that in Asian amphibians co-existing with Bd, skin bacteria and fungi shift with infection and may help defend against chytridiomycosis. Shared anti-Bd bacteria and denser microbial networks could contribute to host tolerance. This knowledge may inform efforts to mitigate chytridiomycosis in more vulnerable amphibian populations elsewhere. Most associations were correlative, so the microbiome's protective role is not proven. Sampling was limited, few uninfected individuals were available, and broader host sampling is needed to confirm the patterns.