The overuse of antibiotics has led to an increasing number of antibiotic-resistant bacteria, adding a tremendous burden to the cost of healthcare in the United States. According to the Centers for Disease Control and Prevention’s 2019 report, 2.8 million people in the U.S. are infected with antibiotic-resistant strains of bacteria, killing more than 35,000 per year. To combat this growing issue, bioprospecting can be implemented to discover new antimicrobial compounds. Our project has employed this strategy to test extracts from lichens, fungi, liverworts, ferns, and angiosperms collected from the Flathead Valley for their antimicrobial properties. Using Kirby-Bauer disk-diffusion assays, extracts are tested for their ability to inhibit the growth of four Gram-positive and two Gram-negative bacterial species. Building on the work conducted by FVCC students, our research has performed disk diffusion assays on 65 species with 44 species displaying antimicrobial activity. Our research is currently focused on four specimens, Lyophyllum, Ceanothus, Polystichum and Pteridium, which have the potential to provide novel antimicrobial compounds. We are also using microtiter-based minimal inhibitory concentration (MIC) assays to gain a quantitative measure of inhibition and to correlate to disk diffusion data. The ultimate goal of this research is to identify the antimicrobial compounds present in the extracts.
