(483a) Designing Better Biocides to Promote Agricultural Biodiversity and Food Security

Biofilm and modifications of the cell wall are some of the natural defense mechanisms of pathogens that contribute to antimicrobial resistance, pose a threat to pre- and post-harvest agriculture, and contribute to foodborne illness. Current antimicrobials are ineffective in removing biofilm, leading to antimicrobial overuse and increasing antimicrobial resistance. Moreover, the stress on food production due to a changing climate and population growth exacerbates antimicrobial overuse and emergence of multi-drug resistant pathogen, as well as degrading soil, water and reducing agricultural biodiversity needed to protect against pathogens. Increasing temperatures are linked to changes in microbial pathogen adaptation and distribution that can lead to increased foodborne illness, and increased stress on crops due to drought and salinity stress reduces their robustness to ward off pathogens. Increasing pesticide use to compensate for this vulnerability leads to degradation of soil microbiomes, which are critical for nutrient recycling and sustaining soil health, as well as making plants more vulnerable to infection by resistant pathogens able to spread further and overwinter due to increased temperatures. Thus, there is a critical need to develop effective tools to detect and remove pathogens that are sustainable, safe and effective, particularly in the face of increasing resistance.

In this talk, I will first discuss our work identifying and characterizing the evolution of biofilm formation, virulence and spite in S. maltophilia, an emergent, nosocomial pathogen associated with respiratory infections, contamination of water purification systems and plant stress tolerance as well plant pathogenicity. In particular, I will focus on the evolution of polysaccharide processing enzymes in S. maltophilia and their adapation to a wide range of substrates, including biofilm exopolysaccharides, hyaluronic acid and plant polysaccharides. Using a structure-guided approach, we have developed a model for how S. maltophilia has evolved these enzymes to adapt to a pathogenic niche for both plants and humans, and their impact on human health. Second, I will describe our work designing enzymes with broad-spectrum activity against a wide range of polysaccharides found in bacterial biofilms and cell wall structures as antimicrobials. In particular, I will discuss the development of enzymes capable of selectively removing biofilm from multiple foodborne pathogens, as well as engineering of these enzymes to target pathogen cell wall directly, and highlight applications we have commercialized for enhanced detection of foodborne pathogens such as Listeria monocytogenes as well as ongoing work eliminating pathogens from food. Additionally, I will highlight ongoing work developing novel biocides for pre-harvest crop protection targeting highly resistance pathogens such as Erwinia amylovora, the causative agent of fire blight.