Bacterium
Cutibacterium acnes
Acne & prosthesis anaerobe (formerly Propionibacterium)
koo-tih-bak-TEER-ee-um AK-neez
High-yield clue
Slow-growing anaerobic skin rod tied to acne and to indolent prosthetic (especially shoulder) infections, and a notorious blood-culture contaminant that requires long incubation.
Overview
A slow-growing anaerobic Gram-positive rod of the skin (renamed from Propionibacterium acnes) that lives in pilosebaceous follicles. It is a key teaching example of a skin commensal that is both an acne contributor and an indolent implant pathogen.
Classification
- Gram-positive
- Rod
- Anaerobic / aerotolerant
- Skin flora
Lab & identification clues
- Slow-growing anaerobe needing prolonged incubation
- Gram-positive rod
- Contaminant vs true pathogen framing
- Biofilm on implants
Associations
- Acne vulgaris in pilosebaceous units
- Prosthetic joint / shoulder implant infection
- Blood-culture contaminant framing
Commonly confused with
- Coagulase-negative staphylococci contaminants
- Corynebacterium species
Frequently asked questions
What is Cutibacterium acnes?
A slow-growing anaerobic Gram-positive rod of the skin (renamed from Propionibacterium acnes) that lives in pilosebaceous follicles. It is a key teaching example of a skin commensal that is both an acne contributor and an indolent implant pathogen.
What is the Gram stain of Cutibacterium acnes?
Cutibacterium acnes is Gram positive.
What are the lab clues for Cutibacterium acnes?
Lab clues for Cutibacterium acnes include Slow-growing anaerobe needing prolonged incubation, Gram-positive rod, Contaminant vs true pathogen framing, and Biofilm on implants.
What is Cutibacterium acnes commonly confused with?
Cutibacterium acnes is commonly confused with Coagulase-negative staphylococci contaminants and Corynebacterium species.
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.