Submitted to: American Dairy Science Association Discover Conference
Publication Type: Abstract Only
Publication Acceptance Date: 9/22/2003
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Since the advent of antibiotics, both the health care and agriculture sectors have relied heavily on these agents to control bacterial pathogens. However, increasing levels of resistance have reduced the efficacy of antibiotics. Bacteriophage therapy is an 'old' idea undergoing a revival. Lytic bacteriophages are viruses that attach to specific surface receptors on bacteria, inject their DNA, and express genes that lead to the synthesis of new phage particles. The process ends with lysis (death) of the host cell and the release of dozens or hundreds of new phages. Phages are highly specific, often only active against a subset of strains within a species, which allows for the removal of the targeted microorganisms from a mixed population. Unlike antibiotics that decay over time and distance, phage numbers actually increase as long as susceptible bacteria are present. Further, phage are living entities that adapt and evolve; if mutants of the pathogen evolve, the phage will similarly adapt. In this presentation, we discuss a new way to reduce E. coli O157:H7 concentrations in livestock through the use of bacteriophages. Phage CEV1 was isolated from the feces of sheep resistant to gastrointestinal colonization by O157:H7 strains that had previously been used as standard gut colonizers. Phage CEV1 infects >90% of the O157:H7 strains tested, and a small number of other E. coli strains. Preliminary trials of CEV1 and CEV2 to evaluate their use as a potential management strategy in vitro and in vivo have been highly successful. Treated sheep showed a substantial reduction in intestinal levels of O157:H7 with a single oral dose of CEV1 within 2 days. These results indicate the protective effect of bacteriophages against E. coli O157:H7.