Data from: Disruption of skin microbiota contributes to salamander disease

Escalating occurrences of emerging infectious diseases underscore the
importance of understanding microbiome-pathogen interactions. The
amphibian cutaneous microbiome is widely studied for its potential to
mitigate disease-mediated amphibian declines. Other microbial interactions
in this system, however, have been largely neglected in the context of
disease outbreaks. European fire salamanders have suffered dramatic
population crashes as a result of the newly emerged Batrachochytrium
salamandrivorans(Bsal). We investigate microbial interactions on multiple
fronts within this system. We show that wild, healthy fire salamanders
maintain a complex skin microbiota containingBsal-inhibitory members, but
the community is present at remarkably low abundance. Through
experimentation, we show that increasing bacterial densities of
Bsal-inhibiting bacteria via daily addition slowed disease progression in
fire salamanders. Additionally, we find that experimental-Bsal infection
elicited subtle changes in the skin microbiome, with selected
opportunistic bacteria increasing in relative abundance resulting in
septicemic events that coincide with extensive destruction of the
epidermis. These results suggest that fire salamander skin, in natural
settings, maintains bacterial communities at numbers too low to confer
sufficient protection againstBsal,and in fact the native skin microbiota
can constitute a source of opportunistic bacterial pathogens that
contribute to pathogenesis.By shedding light on the complex interaction
between the microbiome and a lethal pathogen, these data put the interplay
between skin microbiomes and a wildlife disease in a new perspective.