1a. Objectives (from AD-416)
The objectives of this work include 1) Determine the efficacy of bacteriophage to prevent and treat colibacillosis (Escherichia coli); 2) Determine the efficacy of bacteriophage to prevent and treat turkey coryza (Bordetella avium);and 3) Determine the efficacy of bacteriophage to prevent and treat fowl cholera (Pasteurella multocida).
1b. Approach (from AD-416)
Bacteriophage will be isolated from environmental sources targeted for the bacteria E. coli, Bordetella avium, and Pasteurella multocide. Using our established colibacilosis model we will quantitatively determine the relationship between bacteriophage titers to therapeutic efficacy by treating colibacillosis with different bacteriophage titers, and will conduct in vitro studies to determine if there are any non-specific blood factors that inhibit bacteriophage activity. The efficacy of repeated treatment of bacteriophage will be conducted by administering bacteriophage prior to challenging the birds with the disease agent, and then treating them with an additional bacteriophage administration to determine if prior exposure to high titers of bacteriophage will limit the efficacy of bacteriophage to treat colibacillosis. Bacteriophage from environmental sources will be isolated with effectiveness against Bordetella avium and Pasteurella multocida. Studies will be conducted to determine the efficacy of aerosol administration of bacteriophage to prevent disease by administrating the bacteriophage prior to challenging the birds with Bordetella avium or Pasteurella multocida.
3. Progress Report
During this year progress was made on the establishment of a new model to study the efficacy of bacteriophage to both prevent and treat respiratory diseases. We are now reasonably certain that we have developed a new model to study the efficacy of bacteriophage to prevent and treat colibacillosis. This model should improve the repeatability and accuracy of reproducing this disease over our current model. In addition, it should be a more natural model that better mimics the etiology of the disease in nature. Preliminary studies to test the efficacy of this model were disappointing, and after consideration of this work some modifications to our model are necessary. We still believe that this new model can be developed and will allow us to obtain data on the ability of bacteriophage to prevent and treat this disease, which will be a better prediction of the efficacy of bacteriophage in the real world. We have also made progress on the development of in vitro tests to document the degree of immune interference on bacteriophage efficacy. We have provided E. coli isolates collected from field cases of colibacillosis. Periodic meetings with our CRADA partner occur, and at this time our CRADA partner is pursuing outside funding that will allow them to conduct the research agreed to. We are working together to prepare the grant applications.
1. Bacteriophage Therapy: There is a need to find alternatives to the use of antibiotics in poultry production, since there is concern that this practice contributes to the emergence of antibiotic resistance in bacteria of human clinical significance. Bacteriophage are viruses that kill bacteria and provide a natural and safe alternative to antibiotics. Colibacillosis is an important disease in poultry that we use as a model to critically evaluate the efficacy of bacteriophage to both prevent and treat this disease. We developed a new model to produce colibacillosis that challenges the birds with E. coli by trachea gavage. This model is a more natural and reproducible model that should allow us and the research community an important experimental method to study colibacillosis in poultry. Preliminary work on the efficacy of bacteriophage to prevent colibacillosis using our new model was disappointing, and after careful evaluation of these data modification will be made and studies on the efficacy of bacteriophage will be conducted. This work on the efficacy of bacteriophage to prevent colibacillosis in day of age chicks addresses a critical concern on the commercial potential of this approach to reduce the impact of colibacillosis on the poultry industry.
Blanco, J.M., Wildt, D.E., Hoefle, U., Voelker, W., Donoghue, A.M. 2009. Implementing artificial insemination as an effective tool for ex situ conservation of endangered avian species. Theriogenology. 71:200-213.