Looking at different sites of where this colonizes,
New data on C. acnes taxonomy
https://onlinelibrary.wiley.com/doi/full/10.1111/jdv.15043
Among the multiple commensal microorganisms present in the healthy skin flora, P. acnes / C. acnes is a ubiquitous gram‐positive anaerobic bacterium belonging to the Actinobacteria phylum, that predominantly resides deep within the sebaceous follicle in contact with keratinocytes.3 Conversely, at the skin surface Propionibacteria are less represented (<2% of all bacteria), in favour of Staphylococci , especially Staphylococcus epidermidis ( S. epidermidis ), which dominate with >27% of the total bacteria population.11 P. acnes / C. acnes is also found in other tissues such as intestine, stomach, lungs, mouth, conjunctiva, prostate and urinary tract.3, 12-14 Specific metabolic features allow P. acnes/C. acnes to colonise the hostile lipid‐rich sebaceous follicle environment and protect skin from other harmful pathogens to preserve the stability of resident skin microbiota.3, 4 In particular, it can degrade triglycerides present in sebum to generate short‐chain fatty acids, including propionic acid, which accumulation participates in the maintenance of an acid skin pH. Despite active research as P. acnes/C. acnes has been hypothesised as an important pathogenic factor in acne,15 its contribution to acne pathophysiology is not clearly established while its protective role as a commensal bacterium of healthy skin microbiota has been confirmed.3