Cutibacterium acnes periprosthetic joint infections.

Area of Science:

• Infectious Diseases
• Orthopedic Surgery
• Microbiology

Background:

• Periprosthetic joint infections (PJIs) caused by Cutibacterium acnes (C. acnes), formerly Propionibacterium acnes, are increasingly recognized but can be under-reported.
• Distinguishing true C. acnes infections from culture contamination is crucial for appropriate management.

Purpose of the Study:

• To describe the patient demographics and treatment outcomes for hip and knee PJIs caused by C. acnes.
• To evaluate the effectiveness of different treatment strategies for C. acnes PJIs.

Main Methods:

• Retrospective review of patients with C. acnes PJI between 2005 and 2018.
• Inclusion criteria required monomicrobial PJI with at least two positive cultures; polymicrobial infections or single positive cultures were excluded.
• Analysis included 35 cases (21 hips, 14 knees) with a mean follow-up of five years.

Main Results:

• The median time to positive culture for C. acnes was five days.
• Common laboratory markers (ESR, CRP, synovial fluid cell count) were consistent with infection.
• Treatment involved chronic antibiotic suppression (51%) or two-stage exchange arthroplasty; two-year survival free of revision was 94%.

Conclusions:

• Laboratory findings for C. acnes PJI were typical, and cultures may grow faster than previously assumed.
• Both chronic antibiotic suppression and two-stage exchange arthroplasty demonstrated favorable mid-term treatment success rates with low failure rates.