Inclusion Criteria:

1. Hip or knee Prosthetic joint infection treated by debridement, antibiotic therapy initiation and retention of prothesis (DAIR strategy)

2. Infected with at least one of the following microorganisms:

   1. Staphylococcus aureus
   2. Coagulase-negative staphylococci

3. Microorganisms susceptible to rifampicin and at least one other antibiotic suitable for the treatment of PJI (e.g., penicillin, fluoroquinolone, (doxy/mino)cycline, oxazolidinone, cotrimoxazole, daptomycin, glycopeptide, macrolide, fusidic acid), regardless of sensitivity to methicillin.

4. Age ≥ 18 years

5. At least 2 days of appropriate (i.e., covering pathogen(s) identified in the intraoperative samples) empirical agents are needed. Pre-randomization antimicrobial therapy could be: flucloxacillin, oxacillin, vancomycin, daptomycin. β-lactam plus β-lactamase-inhibitors (e.g. ampicillin+sulbactam, piperacillin+tazobactam), cephalosporins (except ceftazidime), carbapenems, teicoplanin, ceftaroline, ceftobiprole.

6. Signed Inform consent

7. Patient having the rights to French social insurance

8. For women of childbearing potential i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile and excluding oestroprogestative-based contraception, any effective contraceptive: vasectomy (for men), intrauterine device copper, feminine sterilization, condom, sexual abstinence is required. A postmenopausal state is defined as no menses for 12 months without an alternative medical cause

Exclusion Criteria:

1. Suspicion of reduce absorption of oral treatment due to abdominal disorder Known or suspected malabsorption (imperfect absorption of food material by the small intestine)
2. Polymicrobial infection due to other than staphylococcus species susceptible to rifampicin
3. Known or suspected allergy to rifabutin and/or rifampicin
4. Diagnosis of endocarditis associated to PJI
5. Renal transplant or Chronic kidney disease with an eGFR of less than 30ml/min/1.73m²
6. Other Solid Organ Transplant
7. Liver cirrhosis, Child-Pugh score C
8. Any other concomitant infection which required a prolonged course of intravenous antibiotic therapy
9. Oestroprogestative-based contraception
10. Oral anticoagulant drugs
11. Other drug-drug interaction that contraindicated rifampicin or rifabutin
12. Porphyria
13. Unable to take oral treatment
14. Receive empirical postoperative antibiotic treatment by rifampicin or rifabutin prior to randomization
15. Pregnancy or lactating women
16. Curator or guardianship or patient placed under judicial protection
17. Participation in other interventional research during the study