Successful systemic phage therapy for implant-associated MRSA spondylodiscitis

To describe the first experience with systemic bacteriophage therapy in a patient with chronic vertebral osteomyelitis caused by methicillin-resistant Staphylococcus aureus (MRSA) and limited antibiotic treatment options.

We report a case of a 60-year-old polymorbid woman with chronic MRSA vertebral osteomyelitis associated with non-removable spinal instrumentation. The patient had previously received multiple antibiotic regimens, including prolonged linezolid therapy, and developed hypersensitivity to most available antibiotics. Due to persistent infection, individualized intravenous antistaphylococcal bacteriophage therapy was administered as an innovative treatment approved by the national regulatory authority. The patient received 35 intravenous doses of 10⁹ plaque-forming units (PFU).

Systemic bacteriophage therapy was well tolerated, with no adverse events observed. The treatment resulted in sustained clinical improvement and normalization of inflammatory markers. Six months after completion of bacteriophage therapy and discontinuation of all antibiotics, the patient remains in good clinical condition without signs of infection relapse.

This case demonstrates the potential role of systemic bacteriophage therapy as a safe and effective treatment option for deep-seated, antibiotic-refractory MRSA infections. It also provides a practical framework for regulatory approval and clinical use of individualized phage therapy in complex infectious diseases.