Abstract
We examined the activity of phages to control the growth of chicken and swine Salmonella strains in avian (CHIC-8E11), porcine (IPEC-1), and human (HT-29) cell cultures. We optimized a six-phage cocktail by selecting the five most effective myoviruses and a siphovirus that have optimal lysis on prevalent serovars. We observed ∼20% of 7 log(10) PFU/well phage and 3-6 log(10) CFU bacterial adhesions, and 3-5 log(10) CFU bacterial invasion per 2 cm(2) of the cultured cells at 2 h post-treatment. The invasive bacteria when plated had a variable reduced susceptibility to the phages. After phage application at an MOI of 10, the prophylaxis regimen had better efficacy at controlling bacterial growth with an up to 6 log(10) CFU/well reduction as compared with the 1-2 log(10) CFU/well bacterial reduction observed in the remedial and coinfection regimens. Our data support the development of these phages to control salmonellosis in chickens, pigs, and humans.