Isolation and Use of Bacteriophage to Reduce E. Coli O157:H7 Populations on Hides of Cattle

Findings: E. coli O157:H7 is an important foodborne pathogenic bacteria that lives in the gut and can be found on the hides of cattle, potentially entering the food chain via this reservoir. Bacteriophages are viruses that kill certain bacteria, such as E. coli O157:H7. We have previously used phages isolated from cattle feces as a method to reduce E. coli O157:H7 in cattle. The present study examined if phages isolated from cattle could be used to reduce E. coli O157:H7 on their hides. In this study, we were unable to demonstrate that our phages could reduce E. coli O157:H7 populations on the hides of cattle. We think that the low nutrient density of the hide and the oxygen-rich conditions may have created multiple hurdles to the bacteria-killing action of our phages that were insurmountable for a phage of intestinal origin. Recently a company has received FDA approval for a phage product to reduce E. coli O157:H7 on cow hides. Their product (having passed FDA trials) is an indication that this project was a worthwhile concept and expenditure of funds, but that the best source for phages for use on the hides may have been from somewhere other than the cattle themselves.