Streptococcus vulneris sp. nov., isolated from wound of patient with diabetic foot ulcer (DFU).

A new α-haemolytic streptococcal strain, designated DM3B3, was isolated from the wound of a diabetic foot ulcer (DFU) patient. Phylogenetic analysis based on 16S rRNA full-gene sequencing (1563 bp) revealed highest sequence similarity to Streptococcus mitis (99.7%), followed by "Streptococcus gwangjuense" (99.6%), and Streptococcus pseudopneumoniae (99.5%). Comparison of five housekeeping genes, groEL, rpoB, sodA, recA and pheS, revealed that strain DM3B3 was well separated from the Streptococcus reference strains. The complete genome of strain DM3B3 consisted of 1,963,039 bp with a G + C content of 41.0 mol%. Average nucleotide identity values between strain DM3B3 and Streptococcus mitis NCTC 12261, "Streptococcus gwangjuense" ChDC B345, and Streptococcus pseudopneumoniae ATCC BAA-960 were 93.8%, 94.4%, and 92.2%, respectively. The highest digital DNA-DNA hybridization value with respect to the closest species was 57.5%, i.e., below the species cut-off of 70% hybridization. The main cellular fatty acids of strain DM3B3 were 16:0, 18:1ω7c, 18:1ω9c and 18:0. On the basis of phylogenetic, genotypic and phenotypic data, we propose to classify this isolate as representative of a novel species of the genus Streptococcus, Streptococcus vulneris sp. nov., in reference to its isolation from wound, with strain DM3B3 (= NBRC 114638 = BCRC 81288) as the type strain.