Characterization and partial genomic analysis of a lytic Myoviridae bacteriophage against Staphylococcus aureus isolated from dairy cows with mastitis in Mid-east of China.

Using bacteriophages as a tool to the control of pathogens is a complementary to antibiotic therapy. We have isolated a lytic bacteriophage, designated vB_SauM_JS25, from sewage effluent on a dairy farm in Jiangsu, Mid-east of China for use as a biocontrol agent against Staphylococcus aureus infections. Phage vB_SauM_JS25 was morphologically classified as Myoviridae. The phage showed broad host ranges within S. aureus strains, lysing 51 of 56 strains (91.1 %). Its latent period and burst size were approximately 20 min and 21 PFU/cell, respectively. Phage vB_SauM_JS25 was able to survive in a pH range between 6 and 9. However, a treatment of 70 or 80 °C for 10 min completely inactivated the phage. Moreover, morphologic analysis of vB_SauM_JS25 revealed that it was closely related to other Myoviridae phages infecting Staphylococcus species. The bacteriolytic activity of phage vB_SauM_JS25 at a multiplicity infection (MOI) 1 indicted its efficiency for reducing bacterial growth. These findings suggest that phage vB_SauM_JS25 could be considered a potential therapeutic or prophylactic candidate against S. aureus infection.