Risk factors for Cutibacterium acnes spinal implant-associated infection: a case-case-control study

Area of Science:

• Infectious Diseases
• Orthopedic Surgery
• Microbiology

Background:

• Spinal implant-associated infections (SIAIs) pose significant challenges in orthopedic surgery.
• Cutibacterium acnes (C. acnes) is an increasingly recognized pathogen in SIAIs, often associated with distinct clinical characteristics.

Purpose of the Study:

• To identify the specific characteristics of patients who develop C. acnes SIAI.
• To determine the risk factors associated with C. acnes SIAI development.

Main Methods:

• Two parallel case-control studies were conducted.
• Cases included patients with C. acnes SIAI (n=59) and SIAI from other microorganisms (n=93).
• Controls included patients who underwent spinal instrumentation without infection (n=302).

Main Results:

• C. acnes SIAI cases presented more frequently with late-onset infections (median 843 days vs. 23 days) and less often with fever or wound inflammation.
• Polymicrobial infections were common in C. acnes SIAI (40%), often with co-infecting staphylococci.
• Risk factors for C. acnes SIAI included younger age (<54 years), lower BMI (<22 kg/m²), and thoracic instrumentation.

Conclusions:

• Younger, thinner patients undergoing spinal instrumentation, particularly involving the thoracic spine, are at increased risk for C. acnes SIAI.
• Future research on C. acnes SIAI prevention and treatment should target these specific patient demographics and surgical procedures.