title: Propionibacterium prosthetic joint infection: experience from a retrospective database analysis.
abstract: BACKGROUND
  With improved diagnostic methods and longer prosthesis indwelling time, the frequency of diagnosed Propionibacterium prosthetic joint infections (PJI) is increasing. Data on clinical, microbiological, radiological and surgical treatment are limited, and importance of this organism in PJI is probably underestimated.
  
  
  METHODS
  We retrospectively analyzed patients with PJI caused by Propionibacterium spp. diagnosed at our institution between 2000 and 2012. Patient data were retrieved through chart review, and the outcome was evaluated at patient follow-up visits.
  
  
  RESULTS
  Of 15 included patients (median age 65 years, range 44-87), 8 hip, 4 shoulder, 2 knee and 1 ankle PJI were recorded. The median time from implantation to diagnosis of PJI was 44.2 months (range 2-180 months). Most PJI (8 patients, 53 %) were diagnosed late (>24 months after arthroplasty). Persistent pain was present in 13, local joint symptoms in 8, fever in 4 and sinus tract in 3 patients. Radiological signs of loosening were present in 11 patients (73 %). Organisms were detected in intraoperative biopsy (n = 5), sonication (n = 4) or preoperative joint puncture (n = 4). In three cases coinfection with a coagulase-negative staphylococcus was diagnosed. Revision surgery was performed in all cases. After a mean follow-up of 16 months after revision surgery (range 4-37 months), 14 patients (93 %) showed no signs or symptoms of infection and had a functional prosthesis; one patient experienced a new infection with another organism (Staphylococcus epidermidis).
  
  
  CONCLUSIONS
  Patients with persistent postoperative pain and/or loosening of implants should be screened for PJI with low-virulent organisms such as Propionibacterium, including.
authors.affiliation: Orthopedic Septic Surgical Unit, Department of Surgery and Anesthesiology, Lausanne University Hospital, Lausanne, Switzerland. anna.rienmueller@meduniwien.ac.at.|Department of Orthopedic Surgery, Vienna General Hospital, Medical University Vienna, Waehriger Guertel 18-20, 1090, Vienna, Austria. anna.rienmueller@meduniwien.ac.at.
authors.forename: Anna
authors.initials: A
authors.lastname: Rienmüller
authors.affiliation: Orthopedic Septic Surgical Unit, Department of Surgery and Anesthesiology, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Borens
mesh_terms: D000328:Adult; D000368:Aged; D019643:Arthroplasty, Replacement / Q000009:adverse effects*; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D007595:Joint Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011425:Propionibacterium acnes; D016459:Prosthesis-Related Infections / Q000601:surgery*; D012086:Reoperation; D012189:Retrospective Studies
keywords: Biofilm; Implant; Infection; Propionibacterium acnes