title: Propionibacterium acnes in primary shoulder arthroplasty: rates of colonization, patient risk factors, and efficacy of perioperative prophylaxis.
abstract: BACKGROUND
  Recent literature has shown that Propionibacterium acnes can be cultured from superficial and deep layers of the shoulder. Our aims were to assess the rate of P. acnes colonization in patients undergoing primary shoulder arthroplasty, to identify patient-related risk factors, and to evaluate the efficacy of our perioperative antisepsis protocol.
  
  
  METHODS
  Thirty consecutive patients undergoing primary shoulder arthroplasty were included in our study. Swabs were taken perioperatively (4 superficial and 2 deep wound swabs) and analyzed quantitatively for P. acnes. Cefazolin minimum inhibitory concentration was determined for P. acnes isolates from positive deep cultures.
  
  
  RESULTS
  Twenty-two patients (73%) had positive cultures for P. acnes. Male gender (P = .024) and presence of hair (P = .005) had significantly higher rates of P. acnes superficial cultures. Subjects with positive superficial P. acnes cultures (P = .076) and presence of hair with a history of steroid injection (P = .092) were more likely to have deep P. acnes-positive cultures, but this was not statistically significant. Local topical antisepsis measures did not eradicate P. acnes (P = .12). Mean cefazolin minimum inhibitory concentration for P. acnes was 0.32 μg/mL.
  
  
  CONCLUSIONS
  P. acnes is commonly isolated from the skin and deep surgical wounds of patients undergoing primary total shoulder arthroplasty who have not had previous shoulder surgery. Male gender and presence of hair were significant risk factors for P. acnes colonization. Perioperative local topical antisepsis and cefazolin administration were not effective in eliminating P. acnes colonization.
authors.affiliation: Department of Orthopaedic Surgery, North Shore Hospital, Takapuna, Auckland, New Zealand. Electronic address: kohchuankong@yahoo.com.
authors.forename: Chuan Kong
authors.initials: CK
authors.lastname: Koh
authors.affiliation: Department of Surgery, Pan Am Clinic, Winnipeg, MB, Canada.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Marsh
authors.affiliation: Waitemata DHB Laboratory Services, North Shore Hospital, Takapuna, Auckland, New Zealand.
authors.forename: Dragana
authors.initials: D
authors.lastname: Drinković
authors.affiliation: Department of Engineering Science, University of Auckland, Auckland, New Zealand.
authors.forename: Cameron G
authors.initials: CG
authors.lastname: Walker
authors.affiliation: Department of Orthopaedic Surgery, North Shore Hospital, Takapuna, Auckland, New Zealand.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Poon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D000985:Antisepsis / Q000379:methods*; D001178:Arthroplasty / Q000009:adverse effects*; D002437:Cefazolin / Q000494:pharmacology; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000209:etiology / Q000517:prevention & control*; D006197:Hair; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D019990:Perioperative Care / Q000379:methods; D011425:Propionibacterium acnes / Q000187:drug effects / Q000302:isolation & purification*; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012785:Shoulder Joint / Q000601:surgery*; D012867:Skin / Q000382:microbiology; D000072836:Surgical Wound / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D002437:Cefazolin
keywords: Propionibacterium acnes; antibiotic prophylaxis; cefazolin; primary shoulder arthroplasty; risk factors; steroid injection