Proposal of new combination, Cutibacterium acnes subsp. elongatum comb. nov., and emended descriptions of the genus Cutibacterium, Cutibacterium acnes subsp. acnes and Cutibacterium acnes subsp. defendens

In 2016, division of the genus Propionibacterium into four distinct genera was proposed. As a consequence, the species Propionibacterium acnes was transferred to Cutibacterium gen. nov. as Cutibacterium acnes comb. nov. The three recently proposed subspecies of P. acnes were not, however, accommodated in this proposal. Following a very recent validation of a new combination for C. acnes subsp. defendens and an automatically created C. acnes subsp. acnes, we now propose the new combination, C. acnes subsp. elongatum comb. nov. The type strain of Cutibacterium acnes subsp. elongatum is JCM 18919(T) (=NCTC 13655(T)). On the basis of further genomic and phenotypic (haemolysis and MALDI-TOF mass spectrometry) analyses of these subspecies, we also provide emended descriptions of the genus Cutibacterium Scholz and Kilian 2016, C. acnes subsp. acnes (Gilchrist 1900) Nouioui et al. 2018, and C. acnes subsp. defendens (McDowell et al. 2016) Nouioui et al. 2018.