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Species/Subspecies: Corynebacterium diphtheriae
Etymology: Genus name: club-shaped bakterium (bacterium means small rod).
Species epithet: of diphtheria.
Significance:Diphtheria is nowadays a rare disease in Sweden and other developed countries.
  [Primarily in human medicine]   
Type Strain: ATCC 27010 = NCTC 11397.
Macromorphology (smell): Small, gray and translucent colonies (1-3 mm in diameter). Some strains give hemolysis on blood agar.
Micromorphology: Nonmotile pleomorphic rod (1-8 x 0,3-0,8 µm). Form ramified aggregates, which look like chineese letters).
Gram +/Gram -:G+
Metabolism: Facultatively anaerobic
Other Enzymes: Esculinase -, urease -
Fermentation of carbohydrates:
Fructose ?, mannose ?, xylose -.
Spec. Char.:
Hosts: Humans (primarely children) and cattle (rare)
Disease (Swedish):Difteri hos människa. Mastit och dermatit hos nötkreatur, vilket är sällsynt.
Disease (English):Diphtheria in humans. (Mastitis and dermatitis in cattle, which is rare.)
Clinical Picture:
Virulence Factors: The structural gene for the diphtheria toxins (the tox genes) are carried by a family of closely related corynebacteriophages. The Beta-phage (B-phage) is the most extensively studied phage. A lytic cycle of the phage is not required for production of the diphtheria toxin. The diphteria toxin is a so-called AB toxin, which cleave NAD into nicotinamide and ADP-ribose (ADPR). ADPR is then irreversibly transferred to elongation factor 2 of the host cells and this results in inhibition of protein synthesis. The diphtheria toxin is, therefore, also called ADP-ribosylating toxin.

Lethal dose of the difteria toxin for humans is about 0.1 μg per kg of bodyweight, which is 50-100 times more than the lethal dose for the botulinum neurotoxin.

Genome Sequence:
Acc-noStrainSize (bp)Genome
NC_002935 NCTC 13129 2 488 000 1c + 0 

16S rRNA Seq.:
Acc-noStrainNumber of NTOperon
X81911 (T) 1395 

 Corynebacterium diphtheriae
About 100 species have been described within genus Corynebacterium, which is closely related to the genera Mycobacterium, Nocardia, Rhodococcus and Crossiella.

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Swedish University of Agricultural Sciences