Use of a Bacteriophage Cocktail to Reduce Salmonella Colonization in Experimentally Infected Chickens

Abstract

Antimicrobial-resistant Salmonella is dangerous for animal health with possible transmission from animals to humans. The bacteriophages may be a safe, effective alternative of antibiotics for the treatment and prevention of Salmonella colonization in poultry. The main goal of this work is to study the efficacy of Salmonella phage cocktail in elimination, reduction and prevention of colonization in poultry of the chicken infectious model. Four groups of experimental animals (n=24) were enrolled in this experiment. Chickens of three groups were challenged orally with a single dose of salmonella (10⁶ CFU/chicken). Group I - received orally 1 ml salmonella phage cocktail 10⁹ PFU per chicken on the day before challenge, immediately after the bacterial challenge and 1 treatment per day the next 8 days. Group 2 – treated with the same dose of cocktail for the next 10 days post-challenge. Group 3 - treated with dialysis buffer for 10 days post-challenge (control group 1) and Group 4 - non-infected chickens (control). In each group, 4 chickens were euthanized on days 1, 3, 5, 7, 10 and 21. The cecum of chickens was checked for Salmonella quantification. The experiment results show that the use of phage cocktail before infection (group 1) significantly reduced colonization of Salmonella and show complete and irreversible elimination of the pathogen after 5 days post-challenge. The complete elimination of pathogen was reached on the 7th day of treatment in group 2.