Streptococcus mitis

RANK: Species

TAXONOMY: Terrabacteria group -> Firmicutes -> Bacilli -> Lactobacillales -> Streptococcaceae -> Streptococcus -> Streptococcus mitis


Heterogenous group of viridans type of streptococci that has had taxonomic revisions. Original type strain, NCTC 3165 (= SK51) clustered with Streptococcus gordonii strains. Proposed NCTC 12261 be replacement type strain of S. mitis [2]. Closely related to S. pneumoniae by 16S rRNA comparisons.Alpha-hemolytic colonies (0.7- 1.2 mm diameter) on blood agar and extensive greening on chocolate agar.Commonly found on most surfaces in the human oral cavity and throat [1]. Not usually attributed to disease, especially oral infections.May be involved in infective endocarditis, toxic shock-like syndrome, and neonatal infections. Septicemias have been reported. Identified as a constituent of the oral microbiome by Human Oral Microbiome Database.

This species has been identified as a resident in the human gastrointestinal tract based on the phylogenetic framework of its small subunit ribosomal RNA gene sequences.[PMC 4262072]

Gut associated
Oral microbiome