Biofilm Inhibition: A Compound-Mediated Process (2014)

Undergraduate: Matthew Powers

Faculty Advisor: Elizabeth Shank
Department: Biology

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The development of biofilms, or microbial communities formed within a self-produced extracellular matrix, is an important function for many microbes. Biofilms not only increase antibiotic resistance, but also the ability of microbes to adhere to both abiotic and biotic surfaces. As a consequence, the biofilms of pathogenic bacteria are able to form in biological hosts and on abiotic surfaces such as IV catheters. Quorum sensing has been recognized as an important aspect of communication between bacteria, with these signals ranging from small molecules to proteins, serving a myriad of functions, such as regulation of gene expression. In a previous study, a variety of Bacillus species were found to induce biofilm formation in Bacillus subtilis via small molecule secretion. Taking a complementary approach, I used a co-culture screen to identify soil microbes that inhibit biofilm formation in B. subtilis. This screen uses a strain of B. subtilis with a fluorescent reporter gene that is expressed when biofilm matrix genes are being inhibited. By growing B. subtilis alongside other bacterial isolates on a medium that induces biofilm formation; biofilm-inhibited colonies are easily identifiable via fluorescence. Using fluorescence and phenotypic evidence, I have identified two soil Pseudomonads that inhibit biofilm formation. Current work is now focused on isolating and characterizing the compound(s) responsible for this biofilm inhibition.