Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/21/2006
Publication Date: 8/1/2006
Citation: Huff, W.E., Huff, G.R., Rath, N.C., Donoghue, A.M. 2006. Evaluation of the influence of bacteriophage titer on the treatment of colibacillosis in broiler chickens. Poultry Science. 85:1373-1377. Interpretive Summary: Bacteriophage are viruses that infect and kill bacteria. It is possible that bacteriophage could be developed as a natural and safe alternative to antibiotics to prevent and treat animal and human bacterial diseases. Two studies were conducted to determine the amount of two different bacteriophage (SPR02 and DAF6) that would provide complete treatment efficacy of a disease known as colibacillosis. Varying levels of these bacteriophage were injected intramuscularly after the birds were challenged with E. coli, the bacteria that causes colibacillosis. The highest levels of bacteriophage SPR02 provided complete protection of the birds, with the level of protection decreasing as the levels of bacteriophage decreased. Bacteriophage DAF6 did not provide an effective treatment at any of the levels tested. These studies indicate that not all bacteriophage will provide effective treatments of animal diseases, but some bacteriophage at high levels can provide very effective treatments of animal diseases. Therefore, selected bacteriophage administered at sufficient titers can be effective therapeutic agents and may provide an alternative to antibiotics in the treatment of bacterial diseases.
Technical Abstract: Two studies were conducted to determine the efficacy of bacteriophage SPR02 and DAF6 at varying titers to treat colibacillosis in chickens. In Study 1 the treatments consisted of a control, i.m. injection of bacteriophage SPR02 or DAF6, E. coli airsac challenge, and E. coli challenge followed by treatment at different titers with bacteriophage SPR02 or DAF6. The E. coli challenged birds at 7 d of age were injected with 6 x 10**4 cfu into the left thoracic airsac. Immediately after the birds were challenged with E. coli they were treated by the administration of bacteriophage SPR02 or DAF6 by i.m. injection into the left thigh with 4 x 10**8, 10**6, 10**4, or 10**2 pfu. Study 2 was identical to Study 1 with the exception that the E. coli challenge was increased to 9 x 10**4 cfu, and the titers of SPR02 and DAF6 were slightly less at 3 x 10**8, 10**6, 10**4, and 10**2 pfu. Both studies were concluded when the birds were 3 wk of age. Mortality in the birds challenged with E. coli in Studies 1 and 2 was 48 and 47%, respectively. The only consistently effective bacteriophage treatment was the highest titer (10**8 pfu) of bacteriophage SPR02, significantly reducing mortality compared to the E. coli challenge birds to 7% in both studies, which was not significantly different from the control treatments. These studies indicate that an effective Multiplicity of Infection (MOI ) for i.m. treatment with SPR02 was 10**4 in this experimental model of colibacillosis. Bacteriophage administered at sufficient titers can be effective therapeutic agents and provide an alternative to antibiotics in the treatment of bacterial diseases.