Case 17

Patient # 17 is a 61-year-old female with a chronic, persistently infected right prosthetic knee joint infection with methicillin-sensitive S. aureus (MSSA) present since Dec 2017. It remained infected with draining sinuses despite multiple rounds of IV antibiotics and surgeries. She received two weeks of phage therapy IV twice a day provided by another company and clinically responded. However, a few weeks after stopping phage her infection recurred and this company was not able to supply additional phage. The patient had since developed anti-phage neutralizing antibodies which neutralized 4 APT phage candidates. At the time of surgical debridement, hardware removal, and antibiotic spacer placement on 25September, 2019 and received an intra-operative dose of a single lytic phage. Multiple surgical cultures (surgical) were positive for MSSA. The patient continued and tolerated twice daily IV phage for 4 weeks using this phage and conducted home installation without adverse event. She responded clinically to combined phage and antibiotic therapy and experience a reduction in inflammatory markers (ESR, CRP). However, she subsequently developed recurrent swelling of the right knee for which she underwent aspiration of the knee joint. Synovial fluid was culture negative on 1Nov2019 and had minimal inflammatory cells. Phage was discontinued on 6Nov2019 and IV cefazolin was continued. She was admitted for a fall on November 17, 2019 and was diagnosed with a right hip fracture which required an open reduction and internal fixation. Her right knee was also more swollen and painful since the fall and synovial fluid analysis on 17Nov2019 showed 25,000 WBC/mL with 92% polymorphonuclear cells. On November 22, 2019 her physician reported that the S. aureus infection had cleared but the synovial fluid from the same knee was now culture positive for pan-susceptible P. aeruginosa. The patient received IV cefepime for the P. aeruginosa infection, though the treating physician requested a P. aeruginosa phage for treatment as well. The first dose was administered on February 12th intra-op followed by twice daily IV installations for one week. All her surgical cultures from 12Feb2020 were negative. No adverse events were reported during the treatment.