Propionibacterium acnes: An agent of prosthetic joint infection and colonization

SummaryBackgroundProsthetic joint infection (PJI) can present a diagnostic challenge, especially with slow-growing and poorly virulent bacteria.ObjectiveTo describe the epidemiological, clinical and biological characteristics of Propionibacterium acnes PJI, their treatments and outcomes and compare 2 clinical pictures (according to the time PJI symptoms appeared after the index operation: ≤2 years, >2 years).MethodsWe conducted a cohort study on P. acnes PJI. Diagnosis was based on ≥2 positive cultures of intraoperative specimens taken during revision arthroplasties for infection or presumed aseptic loosening.ResultsFifty patients with prosthetic hip (34), knee (10) or shoulder (6) infections were included and analyzed according to their symptom-free interval: ≤2 years for 35 and >2 years for 15 (mean interval: 11 ± 6 years). The numbers of previous prostheses (p = 0.04) were higher for the shorter-interval group, which had more frequent signs of infection (p = 0.004). These findings suggest infection in most of the patients whose PJI symptoms appeared: ≤2 years after the index operation, and colonization in the majority of those whose symptoms appeared >2 years after index surgery. Treatment combining exchange arthroplasty with prolonged intravenous antibiotics was successful for 92% of the patients.ConclusionP. acnes can cause different types of PJI: late chronic infections, colonization of loosened prostheses and, exceptionally, acute postoperative infections.