[Combination utility of phages GH15 and K against Staphylococcus aureus]

In the present report, we compared the biological characteristic of staphylococci phage GH15 and K. We also determined the therapeutic potential of the combination utility of two phages.

The patterns of GH15 and K were detected using transmission electron microscopy. We also detected the host range and the one-step curve of phage GH15 and K. The lytic ability of mono-phage and phage cocktail was compared in vitro. Finally, the treatment effect of mono-phage and phage cocktail aginst lethal methicillin-resistant Staphylococcus aureus (MRSA) infection in mice was detected.

The length of GH15 tail was longer than that of K either in the state of contraction or noncontraction. GH15 had broader host range than K whereas both possess 7 common host strains. Although the phage cocktail had equivalent bactericidal capacity with mono-phage to most common host strains, the phage cocktail manifested more effective protection against lethal W4661 infection in mice than any mono-phage. A single smaller dose injection of phage cocktail was sufficient to protect mice effectively from fatal infection.

Our results provide strong evidence towards the therapeutic use of phage cocktail as an alternative to antibiotics for acute infection caused by multi-drug resistant Staphylococcus aureus.