title: Propionibacterium acnes: an agent of prosthetic joint infection and colonization.
abstract: BACKGROUND
  Prosthetic joint infection (PJI) can present a diagnostic challenge, especially with slow-growing and poorly virulent bacteria.
  
  
  OBJECTIVE
  To describe the epidemiological, clinical and biological characteristics of Propionibacterium acnes PJI, their treatments and outcomes and compare 2 clinical pictures (according to the time PJI symptoms appeared after the index operation: < or = 2 years, > 2 years).
  
  
  METHODS
  We conducted a cohort study on P. acnes PJI. Diagnosis was based on > or = 2 positive cultures of intraoperative specimens taken during revision arthroplasties for infection or presumed aseptic loosening.
  
  
  RESULTS
  Fifty patients with prosthetic hip (34), knee (10) or shoulder (6) infections were included and analyzed according to their symptom-free interval: < or = 2 years for 35 and > 2 years for 15 (mean interval: 11+/-6 years). The numbers of previous prostheses (p=0.04) were higher for the shorter-interval group, which had more frequent signs of infection (p=0.004). These findings suggest infection in most of the patients whose PJI symptoms appeared: < or = 2 years after the index operation, and colonization in the majority of those whose symptoms appeared > 2 years after index surgery. Treatment combining exchange arthroplasty with prolonged intravenous antibiotics was successful for 92% of the patients.
  
  
  CONCLUSIONS
  P. acnes can cause different types of PJI: late chronic infections, colonization of loosened prostheses and, exceptionally, acute postoperative infections.
authors.affiliation: Service d'Orthopédie et de Traumatologie, Groupe Hospitalier Diaconesses-Croix Saint-Simon, 125, rue d'Avron, 75020 Paris, France. vzeller@hopital-dcss.org
authors.forename: Valérie
authors.initials: V
authors.lastname: Zeller
authors.forename: Ali
authors.initials: A
authors.lastname: Ghorbani
authors.forename: Christophe
authors.initials: C
authors.lastname: Strady
authors.forename: Philippe
authors.initials: P
authors.lastname: Leonard
authors.forename: Patrick
authors.initials: P
authors.lastname: Mamoudy
authors.forename: Nicole
authors.initials: N
authors.lastname: Desplaces
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007430:Intraoperative Care; D007595:Joint Prosthesis / Q000382:microbiology*; D008297:Male; D011425:Propionibacterium acnes / Q000302:isolation & purification / Q000472:pathogenicity*; D012086:Reoperation; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents