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United States Department of Agriculture

Agricultural Research Service

Title: Isolation and Use of Bacteriophage to Reduce E. Coli O157:h7 Populations in Ruminants

Authors
item Callaway, Todd
item Edrington, Thomas
item Brabban, A - EVERGREEN STATE COLLEGE
item Kutter, E - EVERGREEN STATE COLLEGE
item Anderson, Robin
item Nisbet, David

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 12, 2005
Publication Date: January 13, 2006
Citation: Callaway, T.R., Edrington, T.S., Brabban, A.D., Kutter, E.S., Anderson, R.C., Nisbet, D.J. 2006. Isolation and use of bacteriophage to reduce E. coli O157:H7 populations in ruminants. Proceedings of International Conference on Perspectives of Bacteriophage Preparation. p. 72-83.

Interpretive Summary: Bacteriophage are bacterial viruses that can kill specific bacteria. The food-borne pathogenic bacteria E. coli O157:H7 lives in the intestinal tract of cattle, as do bacteriophage that kill E. coli O157:H7. However, the incidence of these E. coli O157:H7 killing phage in commercial cattle is unknown. In the present study, we isolated phage that killed E. coli O157:H7 from 15% of 240 fecal samples collected from commercial feedlot cattle in the central U.S. Selected phage were combined to form a mixed phage cocktail for use in in vivo studies. Phage cocktail (n = 21 phage isolates) inoculated into sheep (n = 24) that were challenged with E. coli O157:H7, had decreased populations of E. coli O157:H7. Collectively, our results indicate that properly selected and implemented phage-therapy can be used to reduce E. coli O157:H7 in food animals. This suggests that phage could be an important element of an integrated pathogen reduction program.

Technical Abstract: Bacteriophage are viruses that prey on bacteria and are specific to the species or even strain level. Bacteriophage that target the food-borne pathogen E. coli O157:H7 have been previously isolated from several environments. However, no systematic survey has been performed to determine the incidence of phage that target E. coli O157:H7 in food animals, or the correlation between these phage and E. coli O157:H7 populations. In the present study we anaerobically isolated phage that targeted E. coli O157:H7 from 15% of fecal samples from 240 fecal samples collected from commercial feedlot cattle in the central U.S. The spectrum of activity of these phage was determined, and these phage were combined to form a cocktail of phage for use in in vivo studies. When a phage cocktail (n = 21 phage isolates) was inoculated into sheep (n = 24) artificially inoculated with E. coli O157:H7, intestinal populations of E. coli O157:H7 were decreased (P < 0.05) in the cecum and rectum. When sheep in a follow up study were dosed with 10**5, 10**6 or 10**7 PFU of the phage cocktail, the cocktail addition at 10**5 PFU (Multiplicity of infection of 10) was the most effective at reducing E. coli O157:H7 populations throughout the gastrointestinal tract. Collectively, our results indicate that properly selected phages can be used to reduce E. coli O157:H7 in food animals. This suggests that phage could be an important of a coherent, integrated pathogen reduction program.

Last Modified: 11/24/2014