title: The challenge of Propionibacterium acnes and revision shoulder arthroplasty: a review of current diagnostic options.
abstract: BACKGROUND
  Propionibacterium acnes is the most common cause of infection after shoulder arthroplasty. Whereas there are several methods that can aid in the diagnosis of P. acnes infection, there is not a single "gold standard" because of the difficulties inherent in identifying this bacterium. We present an evidence-based discussion of the demographic, clinical, and radiographic predictors of P. acnes infection and review the current options for diagnosis.
  
  
  METHODS
  This review was written after a comprehensive analysis of the current literature related to shoulder periprosthetic joint infection and P. acnes identification.
  
  
  CONCLUSIONS
  Of the techniques reviewed, α-defensin had the highest sensitivity in detecting P. acnes infection (63%). C-reactive protein level and erythrocyte sedimentation rate were often normal in cases of infection. Whereas P. acnes can be challenging to successfully diagnose, there are several options that are considered preferable because of their higher sensitivities and specificities. The current gold standard is intraoperative culture, but major advances in molecular techniques may provide future improvements in diagnostic accuracy.
authors.affiliation: Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Margaret V
authors.initials: MV
authors.lastname: Shields
authors.affiliation: Drexel University College of Medicine, Philadelphia, PA, USA.
authors.forename: Leath
authors.initials: L
authors.lastname: Abdullah
authors.affiliation: Rothman Institute Department of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA, USA. Electronic address: surena.namdari@rothmaninstitute.com.
authors.forename: Surena
authors.initials: S
authors.lastname: Namdari
mesh_terms: D000072228:Arthroplasty, Replacement, Shoulder / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D004909:Erythrocyte Indices; D016908:Gram-Positive Bacterial Infections / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D011425:Propionibacterium acnes / Q000302:isolation & purification*; D016459:Prosthesis-Related Infections / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D012086:Reoperation / Q000009:adverse effects; D012680:Sensitivity and Specificity; D023084:alpha-Defensins / Q000097:blood*
chemical_list: D015415:Biomarkers; D023084:alpha-Defensins; D002097:C-Reactive Protein
keywords: Infection; P. acnes; Propionibacterium acnes; arthroplasty; periprosthetic joint infection; shoulder