Immune Interference of Bacteriophage Efficacy When Treating Colibacillosis In Poultry

Authors: Huff, William; Huff, Geraldine; Rath, Narayan; Donoghue, Ann - Annie

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2010
Publication Date: 5/1/2010
Citation: Huff, W.E., Huff, G.R., Rath, N.C., Donoghue, A.M. 2010. Immune interference of bacteriophage efficacy when treating colibacillosis in poultry. Poultry Science. 89(5):895-900.

Interpretive Summary: A study was conducted to determine if prior exposure of broiler chickens with bacteriophage would limit the ability of the same bacteriophage to treat a bacterial disease in poultry known as colibacillosis. There were 5 treatments with 3 replicate pens of 20 birds per pen. The treatments consisted of 1) control; 2) birds treated with bacteriophage at 10 and 17 d of age; 3) birds challenged with E. coli at 17 d of age; 4) birds challenged with E. coli and treated with bacteriophage at 17 d of age; and 5) birds treated with bacteriophage at 10 d of age and challenged with E. coli and treated with bacteriophage at 17 d of age. Colibacillosis was induced by injecting E. coli into the left thoracic airsac. The bacteriophage was administered by injection of into the thigh. The study was concluded 14 d after E. coli challenge when the birds were 31 d of age. Mortality in the birds challenged with E. coli and not treated with bacteriophage was 55% (Treatment 3), bacteriophage therapy significantly reduced mortality to 8% (Treatment 4), which was not significantly different from the two non E. coli challenged controls (3%, Treatment 1, and 2% Treatment 2). However, mortality in the birds administered bacteriophage prior to challenge with E. coli and treated with bacteriophage (Treatment 5) was 33%, which was not significantly different from the birds that were challenged with E. coli and untreated (55%, Treatment 3). A kinetic assay of bacteriophage activity found that serum from birds pretreated with bacteriophage (Treatment 5) inhibited bacteriophage activity. Antibody levels to the bacteriophage in serum from birds pre-treated with bacteriophage (Treatment 2) was significantly higher at all dilutions compared with control serum (Treatment 1). These data demonstrate that prior exposure to bacteriophage will limit bacteriophage therapeutic efficacy, and suggests that the reduced efficacy is due to an immune response to bacteriophage.

Technical Abstract: A study was conducted to determine if prior exposure of broiler chickens with bacteriophage would limit the ability of the same bacteriophage to treat colibacillosis. There were 5 treatments with 3 replicate pens of 20 birds per pen. The treatments consisted of 1) control; 2) birds treated with bacteriophage at 10 and 17 d of age; 3) birds challenged with E. coli at 17 d of age; 4) birds challenged with E. coli and treated with bacteriophage at 17 d of age; and 5) birds treated with bacteriophage at 10 d of age and challenged with E. coli and treated with bacteriophage at 17 d of age. Colibacillosis was induced by injecting 0.1 mL E. coli into the left thoracic airsac containing 1 X 106 cfu. The bacteriophage was administered by i.m. injection of 0.1 mL into the thigh providing a dose of 6.8 X 108 pfu. The study was concluded 14 d after E. coli challenge when the birds were 31 d of age. Mortality in the birds challenged with E. coli and not treated with bacteriophage was 55% (Treatment 3), bacteriophage therapy significantly ( P ' 0.05) reduced mortality to 8% (Treatment 4), which was not significantly (P ' 0.05) different from the two non E. coli challenged controls (3%, Treatment 1, and 2% Treatment 2). However, mortality in the birds administered bacteriophage prior to challenge with E. coli and treated with bacteriophage (Treatment 5) was 33%, which was not significantly different (P ' 0.05) from the birds that were challenged with E. coli and untreated (55%, Treatment 3). A kinetic in vitro assay of bacteriophage activity found that serum from birds pretreated with bacteriophage (Treatment 5) inhibited bacteriophage activity. IgG levels to the bacteriophage in serum from birds pre-treated with bacteriophage (Treatment 2) was significantly higher at all dilutions compared with control serum (Treatment 1). These data demonstrate that prior exposure to bacteriophage will limit bacteriophage therapeutic efficacy, and suggests that the reduced efficacy is due to an immune response to bacteriophage.