Bacteriophage ΦSA012 Has a Broad Host Range against Staphylococcus aureus and Effective Lytic Capacity in a Mouse Mastitis Model

Abstract

Bovine mastitis is an inflammation of the mammary gland caused by bacterial infection in dairy cattle. It is the most costly disease in the dairy industry because of the high use of antibiotics. <i>Staphylococcus aureus</i> is one of the major causative agents of bovine mastitis and antimicrobial resistance. Therefore, new strategies to control bacterial infection are required in the dairy industry. One potential strategy is bacteriophage (phage) therapy. In the present study, we examined the host range of previously isolated <i>S. aureus</i> phages ΦSA012 and ΦSA039 against <i>S. aureus</i> strains isolated from mastitic cows. These phages could kill all <i>S. aureus</i> (93 strains from 40 genotypes) and methicillin-resistant <i>S. aureus</i> (six strains from six genotypes) strains tested. Using a mouse mastitis model, we demonstrated that ΦSA012 reduced proliferation of <i>S. aureus</i> and inflammation in the mammary gland. Furthermore, intravenous or intraperitoneal phage administration reduced proliferation of <i>S. aureus</i> in the mammary glands. These results suggest that broad host range phages ΦSA012 is potential antibacterial agents for dairy production medicine.