a1 Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, Ontario, N1G 3W4, Canada
a2 Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
a3 USDA, ARS, Poultry Production and Product Safety Research Unit, Poultry Science Center, University of Arkansas, Fayetteville, AR 7270, USA
The successful use of virulent (lytic) bacteriophages (phages) in preventing and treating neonatal enterotoxigenic Escherichia coli infections in calves, lambs and pigs has prompted investigation of other applications of phage therapy in food animals. While results have been very variable, some indicate that phage therapy is potentially useful in virulent Salmonella and E. coli infections in chickens, calves and pigs, and in control of the food-borne pathogens Salmonella and Campylobacter jejuni in chickens and E. coli O157:H7 in cattle. However, more rigorous and comprehensive research is required to determine the true potential of phage therapy. Particular challenges include the selection and characterization of phages, practical modes of administration, and development of formulations that maintain the viability of phages for administration. Also, meaningful evaluation of phage therapy will require animal studies that closely represent the intended use, and will include thorough investigation of the emergence and characteristics of phage resistant bacteria. As well, effective use will require understanding the ecology and dynamics of the endemic and therapeutic phages and their interactions with target bacteria in the farm environment. In the event that the potential of phage therapy is realized, adoption will depend on its efficacy and complementarity relative to other interventions. Another potential challenge will be regulatory approval.
(Received October 15 2008)
(Accepted October 19 2008)