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C-DI-GMP SIGNALING IN E. COLI O157:H7 BIOFILM FORMATION AND COLONIZATION OF THE GASTROINTESTINAL TRACT OF BEEF CATTLE
E. coli O157:H7 induces huge losses to the meat industry and is a threat to consumer safety. Beef product recalls due to E. coli O157:H7 contamination are frequently associated with millions of pounds of product. Further, the runoffs from cattle farms can contaminate vegetables as shown in the 2006 nationwide spinach recall due to E. coli O157: H7 contamination. Since fecal shedding of E. coli O157:H7 from beef is the major source of this pathogen, it is important to reduce E. coli O157:H7 shedding in beef cattle, which depends on the reduction in E. coli O157:H7 gut colonization. On the other hand, biofilms on facility surfaces in processing plants provide a constant source of pathogens, including E. coli O157:H7. Once formed, the biofilm is very difficult to remove; it is resistant to washing and rinsing, chemical detergents and sanitizers. Its presence on facility surfaces and processing environment is a sustained source of contamination. Subsequently, prevention of biofilm formation is another key to beef safety improvement. However, up to now, our knowledge about the mechanisms regulating biofilm formation and gut colonization is very limited. The c-di-GMP molecule is a cytoplasmic second messenger that mediates a myriad of cellular processes. Based on its roles in regulating motility, biofilm formation and virulence gene expression in other pathogens, c-di-GMP signaling is likely involved in E. coli O157:H7 biofilm formation in food processing plants and in cattle gut colonization, which will be tested in the proposed studies. Knowledge obtained from this and subsequent studies will allow us to develop strategies to reduce E. coli O157:H7 contamination in beef and other foods.
USDA CRIS Project Information Link: 0220648