Young-Wook Cho

Use of bacteriophage for biological control of Salmonella Enteritidis infection in chicken

Bacteriophage ΦCJ07 with broad host ranges for Salmonella strains isolated from sewage effluent were used to reduce Salmonella Enteritidis (SE) infection in chickens. One-day-old chicks challenged with 5×10(7) colony-forming units/bird of SE were cohabitated with contact chicks and treated with three concentrations (10(5), 10(7) and 10(9) plaque forming units (PFU)/g) of bacteriophage prepared as a feed additive for 21days after challenge. Salmonella in the intestine was quantified and environmental contamination level was examined at 1, 2 and 3weeks after challenge. All treatments reduced intestinal SE colonization in challenged and contact chickens and reduced the environmental contamination level, but the reductions produced by 10(7) and 10(9)PFU/g of bacteriophage were significant (P<0.05) as compared with untreated controls. In addition, seven out of 10 (70%) contact chickens treated with 10(9)PFU/g of bacteriophage had no detectable intestinal Salmonella at 3weeks after treatment, suggesting that bacteriophage therapy significantly prevented the horizontal transmission of SE. These results provide important insights into preventive and control strategies against SE infection in poultry and indicate that the use of bacteriophage could reduce the incidence of Salmonella food poisoning.

Efficacy of Bacteriophage Therapy on Horizontal Transmission of Salmonella Gallinarum on Commercial Layer Chickens

SUMMARY. A Salmonella Gallinarum (SG)-specific bacteriophage isolated from sewage effluent was used to prevent horizontal transmission of SG in commercial layer chickens. Six-week-old chickens, each challenged with 5 × 108 colony-forming units of SG, cohabited with contact chickens treated with 106 plaque-forming units/kg of bacteriophage, prepared in feed additives, for 7 days before, and 21 days after challenge with SG. Mortality was observed for 3 wk after challenge and SG was periodically re-isolated from the liver, spleen, and cecum of chickens. SG re-isolation from organs was decreased and a significant (P < 0.05) reduction in mortality was observed in contact chickens treated with the bacteriophage, as compared to untreated contact chickens, indicating that bacteriophage administration in feed additives significantly prevented the horizontal transmission of SG. These results provide important insights into prevention and control strategies against SG infection and suggest that the use of bacteriophages may be a novel, safe, and effectively plausible alternative to antibiotics for the prevention of SG infection in poultry.