Propionibacterium acnes in primary shoulder arthroplasty: rates of colonization, patient risk factors, and efficacy of perioperative prophylaxis.

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.
CONCLUSION: 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.