Emerging infectious diseases, particularly fungal infections, pose significant threats to wildlife. Amphibians worldwide are threatened by the fungal skin pathogen Batrachochytrium dendrobatidis. Due to the similarities in cell structure between fungi and animals, fungal infections can be difficult to treat. Targeting chitin, a component of the fungal cell wall that is not found in animal cell walls, may provide one pathway for the development of new treatments. In this study, we investigated the function and diversity of bacterial chitinase genes in a set of bacterial isolates from the amphibian skin microbiome. We analyzed 28 bacterial isolates from the skin of four amphibian species in Virginia. Whole genome annotations predicted that 14 of these isolates contained a total of 45 chitinase genes. We tested the ability of each isolate to degrade chitin in an agar plate assay and found that only six isolates, from two genera (Janthinobacterium and Streptomyces), degraded chitin in this assay. To assess genetic diversity of chitinase genes among our isolates, we screened whole genome assemblies for previously characterized chitinase catalytic and chitin-binding domains. Our analysis identified 15 genes encoding catalytic domains and one gene encoding a chitin-binding domain. These genes were distributed across four bacterial genera: Janthinobacterium, Flavobacterium, Stenotrophomonas, and Streptomyces. Our findings indicate that the chitinase sequences in these isolates belong to GH18 Class II chitinases, the most prevalent class of bacterial chitinases. This research emphasizes the significance of studying microbial interactions and genetic pathways to inform the development of novel strategies for combating wildlife diseases.

‍