Lytic bacteriophages as a potential alternative to control Staphylococcus aureus

Abstract: The objective of this work was to characterize autochthonous bacteriophages and to determine their lytic activity on Staphylococcus aureus. Six phages were isolated from dairy barn flush water through enrichment cultures with three S. aureus strains. All phages were characterized by DNA digestion by restriction enzymes and sequencing of the DNA fragment encoding endolysin. Each phage was tested against 100 S. aureus strains isolated from bovine mastitis and from dairy products using the lysis-plate method. The sequences of the endolysin gene were highly conserved, with nucleotide similarity higher than 99% among the isolated phages. Three domains involved in the recognition and lysis of the bacterial cell wall were identified. Two bacteriophages isolated from the dairy barns present high lytic activity on S. aureus, on a wide range of host strains, indicating their potential for studies on phage therapy in dairy cattle or as a biological control agent for dairy products.