Skin Bacteriome Structure and Batrachochytrium dendrobatidis Prevalence Differs Amongst Two Sympatric Salamanders in the San Francisco Bay Area

Microbial surveys are becoming an important component of wildlife health research, especially in cases where environmental change and infectious diseases are serious issues. Amongst amphibians, Batrachochytrium spp. have the potential to be fatal pathogens that can impact the population health of numerous species. We assessed the skin bacteriome, prevalence of Batrachochytrium dendrobatidis (Bd) and body conditions of two salamander genera with different life histories: the California slender salamander (Batrachoseps attenuatus) and members of the Pacific newt species complex (Taricha torosa and Taricha granulosa; Taricha sp.). We used 16S rRNA V4 amplicon sequencing to characterise the bacterial communities. Taricha sp. had higher prevalence and loads of Bd compared to B. attenuatus, although the prevalence of Bd was restricted to two of the four regions tested. Both salamander types possessed similar bacterial community richness, and the composition of the skin bacteriome varied mostly by region. However, we did find certain associations between the salamander genera and certain ASVs, with mostly members of the family Burkholderiaceae driving the difference. Our results provide additional evidence for the presence of structure in Bd prevalence and bacteriome composition amongst sympatric amphibians that inhabit different microhabitats.