Grant: Discovery Grants Program - Individual

Biofilms are defined as microbial communities adhering and growing on a solid surface while embedding themselves in extracellular polymeric substances (EPS). Compared to planktonic cells, bacteria growing in a biofilm demonstrate increased resistance to desiccation, sanitizers and other antimicrobial agents. In the food industry, biofilms are an increasing concern as they may provide niches in processing environments where pathogens and spoilage organisms can survive for extended periods of time. It has also been demonstrated that biofilm-associated bacteria can detach from food contact surfaces resulting in food contamination. This research will investigate the mechanisms of biofilm formation of the foodborne pathogens Listeria monocytogenes and Campylobacter jejuni. In the next five years, the research will concentrate on the following short term goals: i. to characterize biofilm structures, spatial cell distribution, viability and culturability of single- and mixed species biofilms grown with L. monocytogenes and Pseudomonas spp., ii. to evaluate at the genome- and proteome-level the growth-inhibiting and growth-enhancing effects of Pseudomonas secreted substances on Listeria monocytogenes, iii. to determine the effect of Campylobacter jejuni biofilm growth on strains' ability to survive in aerobic environments and to invade cell cultures, and iv. to investigate the effects of reactive oxygen species on Campylobacter jejuni grown in biofilms. The knowledge gained from the work proposed here will provide the basis to develop effective intervention strategies to minimize and eliminate biofilm growth in food production environments.