Diversity Predicts Ability Of Bacterial Consortia To Mitigate A Lethal Wildlife Pathogen

Abstract

Symbiotic bacterial communities can protect their hosts from infection by pathogens. Treatment of wild individuals with protective bacteria isolated from hosts can combat the spread of emerging infectious diseases, but it is unclear whether the degree of bacterially-mediated host protection is uniform across multiple isolates of globally-distributed pathogens. Here we use the lethal amphibian fungal pathogen Batrachochytrium dendrobatidis as a model to investigate the traits predicting broad-scale in vitro inhibitory capabilities of both individual bacteria and multiple-bacterial consortia. We show that inhibition of multiple pathogen isolates is rare, with no clear phylogenetic signal at the genus level. Bacterial consortia offer stronger protection against B. dendrobatidis compared to single isolates, but critically this was only true for consortia containing multiple genera, and this pattern was not uniform across all B. dendrobatidis isolates. These novel insights have important implications for the effective design of bacterial probiotics to mitigate emerging infectious diseases.