Can phages salvage relapsing S. aureus knee replacements?
Three elderly patients with dead-end relapsing S. aureus prosthetic knee infection improved after DAIR plus an intra-articular three-phage cocktail and suppressive antibiotics.
Source
Phage Therapy as Adjuvant to Conservative Surgery and Antibiotics to Salvage Patients With Relapsing <i>S. aureus</i> Prosthetic Knee Infection
Study at a glance
- Design
- Other — Three consecutive salvage case reports of PhagoDAIR (DAIR plus intra-articular S. aureus phage cocktail) plus suppressive antibiotics; no comparator arm.
- N
- N=3 · Three consecutive elderly patients with relapsing S. aureus prosthetic knee infection (ages 80, 84, 83).
- Population
- Elderly patients with relapsing S. aureus prosthetic knee infection in a therapeutic dead-end (revision not feasible) from the Lyon BJI cohort.
- Outcome
- Clinical infection control, function, and culture/PCR status after PhagoDAIR plus antibiotics and SAT.
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
After ethics/ANSM review, they performed open DAIR, injected a magistral cocktail of lytic phages PP1493, PP1815, and PP1957 (1×10^9 PFU/ml) into the closed joint (PhagoDAIR), then gave 6–12 weeks of combination antibiotics followed by SAT.
What they found
All three had prior DAIR or one-stage exchange failure. After follow-up of 7, 11, and 30 months, function improved markedly. Two needed a later DAIR for mild synovial discharge with sterile cultures; one dual-strain patient kept a mild fistula. No superinfection was documented.
The limits
What it doesn't show
Uncontrolled n=3 salvage series cannot prove phages caused the improvement versus surgery and SAT; polyethylene could not be exchanged, two patients had extra DAIR, and a comparative trial is still needed.
Key terms
- PhagoDAIR
- Debridement, antibiotics, and implant retention plus intra-articular bacteriophage cocktail after joint closure.
- DAIR
- Surgical debridement with implant retention used when prosthesis exchange is not feasible.
- SAT
- Suppressive antimicrobial therapy continued after the intensive postoperative antibiotic course.
- Phagogram
- Lab tests (spot plaque and kinetic assays) of whether a patient’s S. aureus isolate is lysed by candidate phages.
- MOI
- Multiplicity of infection: the ratio of phage particles to bacterial cells in the phagogram assays.
- PJI / PKI
- Prosthetic-joint infection; here specifically prosthetic knee infection due to S. aureus biofilm.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
PhagoDAIR analytic n was:
Common questions
How many patients were treated?
Three consecutive elderly patients (80, 84, and 83 years old).
Which phages were used?
PP1493, PP1815, and PP1957, mixed to 1×10^9 PFU/ml and injected into the joint.
How long was follow-up?
7, 11, and 30 months, with improved walking in all three.
Did infection fully disappear in everyone?
Two became infection-sign free; patient 3 (two S. aureus strains) kept a mild intermittent fistula.
More on Treatment adherence