Corynebacterium diphtheriae

Corynebacterium diphtheriae
Corynebacterium diphtheriae
Gram stained Corynebacterium diphtheriae culture
Scientific classification
Kingdom: Bacteria
Phylum: Actinobacteria
Class: Actinobacteria
Order: Actinomycetales
Family: Corynebacteriaceae
Genus: Corynebacterium
Species: C. diphtheriae
Binomial name
Corynebacterium diphtheriae
Kruse, 1886

Corynebacterium diphtheriae is a pathogenic bacterium that causes diphtheria. It is also known as the Klebs-Löffler bacillus, because it was discovered in 1884 by German bacteriologists Edwin Klebs (1834 – 1912) and Friedrich Löffler (1852 – 1915).



Four subspecies are recognized: C. diphtheriae mitis, C. diphtheriae intermedius, C. diphtheriae gravis, and C. diphtheriae belfanti. The four subspecies differ slightly in their colonial morphology and biochemical properties, such as the ability to metabolize certain nutrients, but all may be toxigenic (and therefore cause diphtheria) or non-toxigenic. The diphtheria toxin gene is encoded by a bacteriophage found in toxigenic strains, integrated into the bacterial chromosome.


In order to accurately identify C. diphtheriae, a Gram stain is performed to show gram-positive, highly pleomorphic organisms with no particular arrangement. Special stains like Alberts's stain and Ponder's stain are used to demonstrate the metachromatic (metachromacity is the phenomenon by which different parts of an organism can get stained in two or more different colours just by applying a single dye) granules formed in the polar regions. The granules are called as polar granules, Babes Ernst Granules, Volutin, etc.). An enrichment medium, such as Löeffler's serum, is used to preferentially grow C. diptheriae. After that, use a selective plate known as tellurite agar, which allows all Corynebacteria (including C. diphtheriae) to reduce tellurite to metallic tellurium. The tellurite reduction is colormetrically indicated by brown colonies for most Cornyebacteria species or by a black halo around the C. diphtheriae colonies.

A low concentration of iron is required in the medium for toxin production. At high iron concentrations, iron molecules bind to an aporepressor on the beta bacteriophage, which carries the Tox gene. When bound to iron, the aporepressor shuts down toxin production.[1] Elek's test for toxogenecity is used to determine whether the organism is able to produce the diphtheria toxin or not.


The bacterium is sensitive to the majority of antibiotics, such as the penicillins, ampicillin, cephalosporins, quinolones, chloramphenicol, tetracyclines, cefuroxime and trimethoprim.

See also

  • Cutaneous diphtheria


  1. ^ Nester, Eugene W.; et al. (2004). Microbiology: A Human Perspective (Fourth ed.). Boston: McGraw-Hill. ISBN 0072473827. 

External links

  • CoryneRegNet - Database of Corynebacterial Transcription Factors and Regulatory Networks

Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Corynebacterium diphtheriae — ? Corynebacterium diphtheriae …   Википедия

  • Corynebacterium Diphtheriae — Corynebacterium diphtheriae …   Wikipédia en Français

  • Corynebacterium diphtheriae — Corynebacterium diphtheriae …   Wikipédia en Français

  • Corynebacterium diphtheriae — Saltar a navegación, búsqueda ? Corynebacterium diphtheriae Cultivo de C. diphtheriae en Ti …   Wikipedia Español

  • Corynebacterium diphtheriae — corynebacterium co ry*ne bac*ter i*um, n. (MIcrobiol.) Any member of the genus {Corynebacterium}, consisting of gram positive usually nonmotile irregularly rod shaped bacteria, some of which are pathogenic or parasitic in humans and domestic… …   The Collaborative International Dictionary of English

  • Corynebacterium diphtheriae — Corynebacterium diphtheriae …   Wikipédia en Français

  • Corynebacterium diphtheriae — C. diphtheriae Corynebacterium diphtheriae Systematik Domäne: Bakterien Abteilung …   Deutsch Wikipedia

  • Corynebacterium diphtheriae — noun a species of bacterium that causes diphtheria • Syn: ↑C. diphtheriae, ↑Klebs Loeffler bacillus • Hypernyms: ↑corynebacterium • Member Holonyms: ↑genus Corynebacterium …   Useful english dictionary

  • Corynebacterium diphtheriae — см. Палочка дифтеритная …   Большой медицинский словарь

  • Corynebacterium diphtheriae — the specific etiologic agent of diphtheria, which also causes skin infections. The organisms are separated according to cultural characteristics into three biovars: mitis, intermedius, and gravis, which apparently are not related to pathogenicity …   Medical dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”