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Our long terms goals are to develop new strategies that will diminish the infectious character of Enterohemorrhagic E. coli (EHEC) through an understanding of the molecular basis of acid resistance in E. coli with emphasis on the superior acid resistance of 0157:H7.
Enterohemorrhagic E. coli (EHEC) cause a variety of dangerous gastrointestinal infections. EHEC Serotype 0157:H7 has recently emerged as an important foodborne pathogen that threatens many aspects of the food industry. A crucial feature of 0157:H7 pathogenesis is its ability to withstand stomach acidity. Our laboratory has identified three systems of acid resistance present in all E. coli and a fourth system dedicated to 0157:H7. Each system will protect cells to pH <2.5 for several hours. We hypothesize that these acid resistance systems are induced during growth within livestock intestines and will persist over long periods of cold storage. One or more of these systems must contribute to the low infectious dose of 0157:H7 by protecting E. coli from gastric acidity and intestinal weak acids.