Description of two novel Corynebacterium species isolated from human nasal passages and skin.

Strains of two novel Corynebacterium species were cultured from samples of human nostrils and skin collected in the United States and Botswana. These strains demonstrated growth on Columbia Colistin-Nalidixic Acid agar with 5% sheep blood and in liquid media (brain heart infusion and tryptic soy broth) supplemented with Tween 80, a source of the fatty acid oleic acid. Cells were Gram-positive, non-spore-forming, non-motile bacilli that showed catalase but not oxidase activity. Major fatty acids in both of these species were 18:1 ω9c (oleic acid), 16:0 (palmitic acid), and 18:0 (stearic acid). Analysis of the 16S ribosomal RNA gene sequences identified these strains as belonging to the genus Corynebacterium (family Corynebacteriaceae). Whole-genome sequencing revealed that these strains formed distinct branches on a phylogenomic tree, with C. tuberculostearicum being the closest relative but with average nucleotide identities of < 95% relative to all previously described species. These results indicate that these strains represent novel species of Corynebacterium, for which we propose the names Corynebacterium hallux sp. nov., with the type strain CTNIH22T (=ATCC TSD-435T=DSM 117774T), and Corynebacterium nasorum sp. nov., with the type strain KPL3804T (=ATCC TSD-439T=DSM 117767T). We also describe the characteristics of two strains isolated from human nasal passages that are members of the recently named species Corynebacterium yonathiae.