title: Presence of Propionibacterium acnes in primary shoulder arthroscopy: results of aspiration and tissue cultures.
abstract: BACKGROUND
  Infection after shoulder surgery has a serious impact on patient outcome and costs associated with care. Propionibacterium acnes infection may be insidious and manifest years after index surgery with resultant joint arthropathy or prosthesis infection. Our goal was to evaluate the presence of P. acnes in a group of patients undergoing primary arthroscopic shoulder surgery to better understand this organism.
  
  
  METHODS
  Samples were collected from 57 patients undergoing first-time shoulder arthroscopy. Demographic data and medical comorbidities were collected. A control, 2 skin swabs, synovial fluid, and 3 tissue samples were obtained. All samples were placed on aerobic plates, on anaerobic plates, and in thioglycolate broth and held for 28 days.
  
  
  RESULTS
  Fifty-seven patients underwent arthroscopic shoulder surgery. The mean age was 51 years. Eighty-one samples (21.8%) were positive for P. acnes when cultures were held 14 days; 32 subjects (56%) had at least 1 culture that grew P. acnes. Positive skin cultures for P. acnes increased from 15.8% before incision to 40.4% at closure. This was even more pronounced in men as positive skin cultures increased from 31.3% before incision to 63.0% at closure. Thirteen patients (22.8%) had more than 3 cultures positive. None of the patients in this study have had signs or symptoms to suggest clinical P. acnes infection.
  
  
  CONCLUSIONS
  Of all subjects studied, 56% had at least 1 positive culture; 21% (of all 371 culture specimens obtained) grew P. acnes. We suspect that it is a consequence of true positive cultures from imperfect skin preparation and dermal contamination.
authors.affiliation: Orthopaedic & Neurosurgery Specialists, ONS Foundation for Clinical Research and Education, Greenwich, CT, USA. Electronic address: Sethi@onsmd.com.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Sethi
authors.affiliation: Section of Infectious Diseases, Greenwich Hospital, Greenwich, CT, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Sabetta
authors.affiliation: Orthopaedic & Neurosurgery Specialists, ONS Foundation for Clinical Research and Education, Greenwich, CT, USA.
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Stuek
authors.affiliation: Orthopaedic & Neurosurgery Specialists, ONS Foundation for Clinical Research and Education, Greenwich, CT, USA.
authors.forename: Storm V
authors.initials: SV
authors.lastname: Horine
authors.affiliation: Orthopaedic & Neurosurgery Specialists, ONS Foundation for Clinical Research and Education, Greenwich, CT, USA.
authors.forename: Katherine B
authors.initials: KB
authors.lastname: Vadasdi
authors.affiliation: Orthopaedic & Neurosurgery Specialists, ONS Foundation for Clinical Research and Education, Greenwich, CT, USA.
authors.forename: R Timothy
authors.initials: RT
authors.lastname: Greene
authors.affiliation: Orthopaedic & Neurosurgery Specialists, ONS Foundation for Clinical Research and Education, Greenwich, CT, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Cunningham
authors.affiliation: Orthopaedic & Neurosurgery Specialists, ONS Foundation for Clinical Research and Education, Greenwich, CT, USA.
authors.forename: Seth R
authors.initials: SR
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011425:Propionibacterium acnes / Q000302:isolation & purification*; D012782:Shoulder / Q000382:microbiology / Q000601:surgery; D012785:Shoulder Joint / Q000382:microbiology* / Q000601:surgery*; D012867:Skin / Q000382:microbiology*; D013582:Synovial Fluid / Q000382:microbiology*; D055815:Young Adult
keywords: P. acnes; Shoulder; arthroscopy; aspiration; culture; infection