Influences of Anti-Bd Bacteria on Amphibians and their Microbiomes

The fungal pathogen Batrochochytrium dendrobatidis (Bd) has been threatening amphibian populations across the globe. Recent work has discovered that bacteria isolated from certain populations of amphibians protect hosts from this pathogen. This project focuses on the anti-fungal mechanisms of Serratia marcescens, a species of bacteria isolated from a Costa Rican frog that dramatically inhibited Bd in culture. Wild-type and recombinant S. marcescens was introduced to the microbiomes of a live amphibian host, Acris blanchardi (Blanchard’s Cricket Frog) and then challenged with Bd to examine the protective effects of this bacteria. The experiment includes recombinant S. marcescens with the genetic pathway responsible for the production of prodigiosin interrupted. This work observed significantly greater movement among frogs treated with wild-type Sm when compared to the other bacteria treatments. There were also significant differences in mean mass and snout-vent length (SVL) between the washed and unwashed treatments. In particular, mean SVL was greater in washed frogs compared to unwashed frogs of the wild-type Sm and no bacteria treatments. These efforts will aid in the future conservation of amphibian species worldwide