Engineered Microbes to Sense and Respond to ETEC

Every year, Enterotoxigenic Escherichia coli (ETEC), the most common form of traveler’s diarrhea, affects thousands of deployed warfighters. The goal is to engineer non-pathogenic E. coli to sense ETEC, respond to its presence, and package it in a cellulose matrix to enable environmental detection of ETEC. We created two plasmids: ‘sense-respond’; and ‘packaging’. The sense-respond plasmid sensed Auto-Inducer 2 (AI-2), a quorum sensing molecule created by most ETEC strains, by expressing LsrR which switches on the Lsr promoter. Activation of the Lsr promoter expresses Super-Folder Green Fluorescent Protein (sfGFP), indicating the presence of ETEC. The packaging plasmid expresses a fusion protein consisting of curli fibers and cellulose binding domains. These modified surface proteins permit the bacteria to bind to cellulose, encapsulating the sense-response module. We envision this genetically engineered machine to be deployed in both the internal and external environment to detect ETEC.