Human Oral Microbiome Taxon Description
Streptococcus mitis
Human Oral Taxon ID (HOT):677Synonym:
Named - Cultured
Type Strain:
NCTC 12261
More info at StrainInfo
NCBI Taxonomy ID:
16S rRNA Sequence:
AF003929  [Entrez Link]
PubMed Search:965  [PubMed Link]
16S rRNA Alignment: View Alignment         Download Alignment         NoteNucleotide Search:6936  [Entrez Nucleotide Link]
Phylogeny: View 16S rRNA tree         View all Tree filesProtein Search:92086  [Entrez Protein Link]
Prevalence by Molecular Cloning:
Clones seen = 1973 / 34879 = 5.66%
Rank Abundance = 2
Genome Sequence
14 View Genomes
Hierarchy Structure:    Hide or show the hierarchy structure
General Information:
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.
Phenotypic Characteristics:
Facultatively anaerobic, Gram positive cocci, approximately 1 um in diameter, that grow in short or long chains in broth cultures.   Carbohydrates are femented primarily to lactic acid and no gas. Catalase negative.  Cell wall contains riitol teichoic acid and minimal rhamnose. Peptidoglycan type is Lys-direct. G+C content is 41 mol%.[2,3]

2 biovars of S. mitis differ biochemically and serologically [2,3]

Prevalence and Source:
Commonly found o­n most surfaces in the human oral cavity and throat [1]. 
Disease Associations:
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. 
PubMed database:
[1] Aas JA, Paster BJ, Stokes LN, Olsen I, Dewhirst FE. Defining the normal bacterial flora of the oral cavity. J Clin Microbiol. 2005 Nov;43(11):5721-32  [PubMed]
Non-PubMed database:
[2] Kilian M, Mikkelsen L, Henrichsen J. Taxonomic study of viridans Streptococci: Description of Streptococcus gordonii sp. nov. and emended descriptions of S. sanguis (White and Niven 1946), S. oralis .... Int J Syst Bacteriol. 1989 Oct;39(4):471-84.  
[3] Hardie RM. Genus Streptococcus. Bergey's Manual of Systematic Bacteriology 1986; Vol. 2, pp. 1043-1063.  
Creation Info:   Latest Modification:  bpaster,  2008-01-10 09:43:14

Copyright 2007-2018 The Forsyth Institute