Advances in understanding Cutibacterium acnes hemolysis: virulence factor or genomic trait?

Background: Cutibacterium acnes is now recognized a major opportunistic pathogen causing a wide range of infections. Henceforth, this bacterium is largely involved in device-related infections especially prosthetic joint infections, spine infections but also cardiovascular infections, neurosurgical implant infections and breast infections. It has also been associated with acne and probably sarcoidosis and prostate tumors. We conducted a narrative review to better understand the phylotypes involved in this clinical entities and if hemolysis can be a diagnosis maker of pathogenicity.

Methods: We searched the PubMed database for English language articles related to C. acnes phylotype and clinical entities and hemolysin characteristic.

Results: As a successful commensal microorganism, C. acnes produces many virulence factors including cytolysins that most likely facilitate tissue damages due to its β-hemolytic trait. In this review, we summarize its involvement in different clinical settings and the role of this virulence factor depending on the phylotype implicated. Our analysis of the literature on C. acnes β-hemolysis clinical strains sheds new light on its potential impact in distinguishing C. acnes infection strains from contaminant strains.

Conclusion: The litterature and our results demonstrate the genetic nature of the β-hemolysis in C. acnes strains rather than being a mean to differentiate virulent clinical strains from commensal or other strains.