Bacterial taxonomy, which defines the category of various microorganisms on the earth and giving appropriate names to them, is a relatively stable area of research. However, the emergence of new investigative technologies, especially whole genome sequencing, resulted in the reassembling of the tower of knowledge of this classical field of research. The separation of the cutaneous group from genus Propionibacterium as a novel genus Cutibacterium is one of the notable examples that taxonomy affects the terminology of clinical dermatology. This caused one of the most major microorganisms on the human skin, Propionibacterium acnes, renamed to Cutibacterium acnes. In addition, several changes of Cutibacterium taxonomy happened in the recent few years, making it difficult for researchers and clinicians to follow.
Our aim of this presentation is to clarify the current status of the genus and the species/subspecies within, so that the participants can fully understand what caused the re-naming of P. acnes to C. acnes and also get familiar with several newly recognized species/subspecies of the genus.
Several articles related to the taxonomy of genus Cutibacterium from 2005 to present are reviewed, including our subspecies proposal of two subspecies of C. acnes in 2015.
First, the reclassification of genus Propionibacterium resulted a breakdown of the genus into four genera, which are Propionibacterium, Acidipropionibacterium, Cutibacterium, and Arachnia. Second, genus Cutibacterium includes four species, C. acnes, C. avidum, C. granulosum, and C. namnetense, and one yet-to-be validated species-level taxon “Propionibacterium humerusii”. Third, C. acnes consists of three subspecies, C. acnes subsp. acnes, C. acnes subsp. defendens, and C. acnes subsp. elongatum. The current status of the genus Cutibacterium estimated to have reached the final stage of the recent change of its taxonomy. Understanding these species and subspecies name and their background is vital to conduct up-to-date dermatological research.

New status quo of taxonomy of bacterial genus Cutibacterium, including Cutibacterium acnes (Propionibacterium acnes) and several other species and subspecies