The present invention describes a genetically modified Staphylococcus aureus bacteriophage VDX-10 comprising the DNA of the bacteriophage VDX-10 being altered by inserting a gene sequence that increases the ability of the bacteriophage to replicate faster as compared to unmodified VDX-10 bacteriophage a method of producing the genetically modified Staphylococcus aureus bacteriophage VDX-10 and a method of treating infection in a patient by administering an amount of the genetically modified Staphylococcus aureus bacteriophage effective to eliminating the Staphylococcus bacteria cells, where the infection can be Ventilator-Associated Pneumonia (VAP) or bacteremia as incited by methicillin-resistant Staphylococcal aureus (MRSA) or methicillin-sensitive Staphylococcal aureus (MSSA).
