title: Propionibacterium acnes infection after shoulder arthroplasty: a diagnostic challenge.
abstract: OBJECTIVE
  This study reviewed a series of patients diagnosed with Propionibacterium acnes infection after shoulder arthroplasty in order to describe its clinical presentation, the means of diagnosis, and provide options for treatment.
  
  
  METHODS
  From 2002 to 2006, 11 patients diagnosed with P acnes infection after shoulder arthroplasty were retrospectively reviewed and analyzed for (1) clinical diagnosis; (2) laboratory data, including white blood cell count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP); (3) fever; (4) number of days for laboratory growth of P acnes; (5) organism sensitivities; (6) antibiotic regimen and length of treatment; and (7) surgical management. Infection was diagnosed by 2 positive cultures.
  
  
  RESULTS
  Five patients had an initial diagnosis of infection and underwent implant removal, placement of an antibiotic spacer, and staged reimplantation after a course of intravenous antibiotics. In the remaining 6 patients, surgical treatment varied according to the clinical diagnosis. When infection was recognized by intraoperative cultures, antibiotics were initiated. The average initial ESR and CRP values were 33 mm/h and 2 mg/dL, respectively. The average number of days from collection to a positive culture was 9. All cultures were sensitive to penicillin and clindamycin and universally resistant to metronidazole.
  
  
  CONCLUSIONS
  Prosthetic joint infection secondary to P acnes is relatively rare; yet, when present, is an important cause of clinical implant failure. Successful treatment is hampered because clinical findings may be subtle, many of the traditional signs of infection are not present, and cultures may not be positive for as long as 2 weeks.
authors.affiliation: Sports Medicine Service, Rothman Institute, Philadelphia, PA 19107, USA. dodsonc@hss.edu
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Dodson
authors.forename: Edward V
authors.initials: EV
authors.lastname: Craig
authors.forename: Frank A
authors.initials: FA
authors.lastname: Cordasco
authors.forename: David M
authors.initials: DM
authors.lastname: Dines
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Dines
authors.forename: Edward
authors.initials: E
authors.lastname: Dicarlo
authors.forename: Barry D
authors.initials: BD
authors.lastname: Brause
authors.forename: Russell F
authors.initials: RF
authors.lastname: Warren
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019643:Arthroplasty, Replacement / Q000009:adverse effects* / Q000379:methods; D002981:Clindamycin / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D015994:Incidence; D007595:Joint Prosthesis; D008297:Male; D010406:Penicillins / Q000627:therapeutic use; D011425:Propionibacterium acnes / Q000302:isolation & purification*; D016459:Prosthesis-Related Infections / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D012189:Retrospective Studies; D018570:Risk Assessment; D012785:Shoulder Joint / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D002981:Clindamycin