UC Santa Cruz

Emerging infectious diseases are a key threat to wildlife. Several fungal skin pathogens have recently emerged and caused widespread mortality in vertebrate species, including amphibians, bats, rattlesnakes, and platypus. The importance of the skin microbiome in host-pathogen interactions is increasingly understood to play a large role in determining the course of disease in a host. White-nose syndrome, caused by the fungal skin pathogen Pseudogymnoascus destructans, threatens several hibernating bat species with extinction and there are no known effective treatments. We co-cultured bacteria and P. destructans from the skin microbiome of four bat species to identify bacterial isolates that might inhibit or kill P. destructans. We then conducted two reciprocal challenge experiments in vitro with six candidate bacteria (all in the genus Pseudomonas) that inhibited P. destructans growth across a range of bacterial and fungal concentrations to quantify the effect of these bacteria on the growth of P. destructans. All six Pseudomonas isolates significantly inhibited growth of P. destructans compared to the non-inhibitory control bacteria, and two isolates performed significantly better than others in suppressing P. destructans growth for more than 35 days. In both challenge experiments, the extent of suppression of P. destructans growth was dependent on the concentration of P. destructans and the initial concentration of the bacterial isolate. These results show that bacteria found naturally occurring on bats can inhibit the growth of P. destructans and have promise for development as a biocontrol for bats exposed to white-nose syndrome. In addition, the presence of these bacteria may influence disease outcome among individuals, populations, and species.