The Escherichia coli species include helpful symbiotes, harmless commensals, and opportunistic or foodborne pathogens. In the gut, the proliferation of pathogenic E. coli, and their potential to induce or contribute to disease, is dependent on the reduction or complete loss of colonization resistance. Colonization resistance is the process by which microbial communities limit the invasion of external microbes or restrict the expansion of specific microbial populations. Host, microbial, and environmental factors can all contribute to lowering colonization resistance to facilitate E. coli expansion, which represents a common hallmark of microbiome dysfunction in many chronic diseases. The host and microbial factors that lower colonization resistance to enhance risk for disease have not been fully defined.

Dr. Melissa Ellermann, Assistant Professor in the Department, was awarded a five year R01 grant from the National Institute of Allergy and Infectious Diseases (NIAID) to conduct a project titled “Effects of host endocannabinoid signaling on Enterobacteriaceae infection”. Her lab will use bacterial genetics and mouse models to define how the host endocannabinoid system can impact colonization resistance in the gut to promote pathogen growth and inflammatory disease. Understanding how this occurs is critical for developing therapeutic strategies that harness the putative beneficial effects of the endocannabinoid system, while also preventing adverse effects that may arise from gut microbiome dysfunction.