ORAL PRESENTER CO-AUTHORS: Eve Milusich, UW-Madison; Bryon Tuthill, UW-Madison; Mary Campbell, Binghamton University; Obed Hernandez-Gomez, Dominican University; Karin Sauer, Binghamton University; Jessica Hua, UW-Madison TITLE: Evolutionary responses of bacteria to antibiotics affect their ability to inhibit a fungal pathogen ABSTRACT: Emerging fungal diseases in wildlife are arising at unprecedented rates. Other microbes in the community (e.g., bacteria) can produce and release anti-fungal compounds influencing fungal disease outcomes. However, changing environmental conditions may alter the inhibitory effectiveness of these compounds. For example, antibiotic contamination of wetlands (i.e., via manure, wastewater treatment plants, human activity) can lead to the evolution of antibiotic-tolerant bacterial strains. Evolving tolerance to antibiotics may allow bacteria to persist when faced with antibiotics but may lead to costs that influence the anti-fungal compounds that are produced. We investigated whether the inhibitory compounds produced by antibiotic-tolerant vs. non-tolerant bacteria (Pseudomonas aeruginosa) differentially influence the growth of an amphibian fungal pathogen found in Wisconsin wetlands (Batrachochytrium dendrobatidis- Bd). We cultured four strains of P. aeruginosa: tolerant and non-tolerant, from both planktonic and biofilm forms. Then we exposed Bd to the bacterial secretions and measured Bd growth after 14 days. We found that secretions from P. aeruginosa strains that have not evolved tolerance to antibiotics inhibited Bd growth. In contrast, secretions from P. aeruginosa strains that have evolved tolerance to antibiotics enhanced Bd growth. Understanding how evolutionary changes in bacteria influence the suite of compounds released into the environment may have important implications concerning the conservation of Wisconsin amphibian communities facing an increased risk from human activities and disease. BIO: Isabela Tuthill is a graduate student at UW-Madison, where she is part of the Hua lab. Isabela received the Science and Medicine Graduate Research Scholars (SciMed GRS) Fellowship in her first semester at UW-Madison. Previously, she attended a semester as a graduate student SUNY Binghamton at Binghamton, NY, where she received the Clark Fellowship.