The anaerobic microorganism Cutibacterium acnes has been increasingly associated with the onset and progression of degenerative disc disease (DDD), though a direct causal link has yet to be confirmed. To clarify the potential pathogenic role of this bacterium, animal models that more accurately reflect human intervertebral disc (IVD) anatomy, physiology, and biomechanics are needed. In this proof-of-concept experiment, we aimed to demonstrate for the first time that C. acnes can be percutaneously injected into sheep IVDs under controlled conditions. Following our established protocol, two sheep received inoculations with a C. acnes strain (8.3 × 10⁶ CFU/disc) originally isolated from a human degenerated disc. No adverse clinical signs were detected. After one month, all three infected discs from the first animal yielded C. acnes growth, although at a reduced bacterial burden (5.12 × 10⁴ to 6.67 × 10⁴ CFU/disc). At six months, cultures from the second animal were negative, suggesting bacterial clearance. These findings confirm that safe, image-guided percutaneous inoculation of C. acnes into ovine IVDs is feasible. Future studies using this model should focus on evaluating whether C. acnes contributes to disc degeneration or associated pathological alterations.
