Abstract
INTRODUCTION: Although Cutibacterium acnes is considered a typical pathogen of postoperative central nervous system (CNS) infections, data on its role as a pathogen, remain limited. This study aimed to address this knowledge gap. METHODS: A case-case-control study of adults with monomicrobial Cutibacterium acnes infections (CaIs) following nonspine neurosurgical procedures (2016-2024) (Cases I). These were individually matched (1:1:1) by age, year, and procedure type to individuals who did not develop infection (controls) and to individuals with aerobic bacterial infections (abIs; cases II). Multivariable conditional logistic regression models were implemented to assess clinical correlates for infection by either bacterial group, clinical presentation, and outcomes differences. RESULTS: Cutibacterium acnes isolation predominantly reflected contamination (131/213, 62%), and ultimately 32 (15%) CaIs cases were included. Smoking (adjusted odds ratio [aOR] 3.25, 95% confidence interval [CI] 1.06-9.97) was the only independent risk factor identified for CaIs. In contrast, nonelective procedure was identified as an independent risk factor for abIs (aOR 6.0, 95% CI 1.34-26.81, p = 0.019). CaIs commonly involved empyema (84% [27/32] versus 53% [17/32] with abIs, p = 0.014). Individuals with CaIs tended to follow a relatively indolent clinical course, were less likely to present with fever (aOR 0.15, 95% CI 0.04-0.68), and had favorable outcomes. When compared with CaIs, patients with abIs were less likely to achieve clinical cure at 90 days (aOR 0.02, 95% CI 0.001-0.41). CONCLUSIONS: Although no modifiable risk factors were identified, CaIs frequently caused empyema, were less likely to present with fever, and were associated with a favorable prognosis.