The Sanger Institute: Corynebacterium diphtheriae, Todar, Kenneth. Morphology and Staining of C. Diphtheriae 2. Murphy, John R. University of Texas Medical Branch: Corynebacterium Diphtheriae, Rollins, David M. University of Maryland: Pathogentic Microbiology: Corynebacterium. Since 1988 Five of the six culture-positive diphtheria cases reported in the United States have been associated with importation of Corynebacterium diphtheriae, an organism believed to have become rare or to have disappeared from the United States. Akers, Angela S., Corynebacterium Akers, Angela S., Esteban, J. et al. A swab from beneath the pseudomembrane is the preferred specimen for culture. Shape – Corynebacterium diphtheriae is a Thin, slender rod-shaped (bacillus) bacterium with a tendency to clubbing at one or both the ends due to the presence of metachromatic granules which may present at one or both the ends.. Corynebacterium diphtheriae is the etiological agent of diphtheria, an upper respiratory disease mainly affecting children. MORPHOLOGY OF CORYNEBACTERIUM DIPHTHERIAE. Many species of Corynebacteria can be isolated from various places such as soil, water, blood, and human skin. Laboratory Diagnosis 6. Sputum, pseudomembrane, nasal and throat swabs, swab from skin lesions. ADVERTISEMENTS: In this article we will discuss about Corynebacterium Diphtheriae which causes a disease called Diptheria in humans:- 1. The difference in virulence of the three strains can be attributed to their relative abilities to manufacture the diphtheria toxin (in both rate and quantity), and their respective growth rates. the following information is not yet verified. Diphtheria is caused by Corynebacterium species, mostly by toxin-producing Corynebacterium diphtheriae and rarely by toxin-producing strains of C. ulcerans and C. pseudotuberculosis. CORYNEBACTERIUM DIPHTHERIAE 6. Frassetto, Lynda A. Corynebacterium Infections. The disease occurs primarily in tropical regions and underdeveloped countries but has been known to appear throughout the world. Due to their snapping type of division, cells often lie in clusters resembling chinese letters. 5. eMedicine. University of Wisconsin-Madison Department of Bacteriology: Diphtheria, From MicrobeWiki, the student-edited microbiology resource, Pseudomembrane at the back of the throat of a child. To avoid the growth of commensals and to differentiate among various biotypes, the sample should be cultured Selective media commonly used are Cystine-Tellurite blood agar or Tinsdale medium. As mentioned in the pathology section, iron plays a key role in regulating the production of the toxin. The disease plagued Europe through the 17th, 18th, and 19th centuries. Please turn on JavaScript and try again. In iron depleted cultures C. diphtheriae will produce the diphtheria toxin as up to 5% of its total protein production. morphology and culture characteristics of corynebacterium diphtheriae (diphtheria bacillus) Besides that of various biochemical reactions and Sugar fermentation tests, certain enzymatic reactions are also medically important to distinguish Corynebacterium diphtheriae from other Corynebacterium sp. A swab from beneath the pseudomembrane is the preferred specimen for culture. morphology and culture characteristics of corynebacterium diphtheriae (diphtheria bacillus) Besides that of various biochemical reactions and Sugar fermentation tests, certain enzymatic reactions are also medically important to distinguish Corynebacterium diphtheriae from other Corynebacterium sp. • Roux and Yersin (1888) discovered the diphtheria exotoxin and established its pathogenic effects. There are three different strains of C. diphtheriae which are differentiated by the severity of the disease they cause in humans. Symptoms often come on fairly gradually, beginning with a sore throat and fever. The three Corynebacterium genomes that have been sequenced are all similar in general content - visit NCBI for more information. The mitis strain has a generation time of about 180 minutes while the gravis strain has a generation time of about 60 minutes. Please enable scripts and reload this page. The tox gene, the structural gene for the diphtheria toxins carried by a family of closely related corynebacteriophages, the most extensively studied being the Beta-phage (B-phage). • The antitoxin was described by von Behring(1890). Esteban, J. et al. Corynebacterium diphtheriae is primarily spread by droplets from coughing or sneezing. The Corynebacterium diphtheriae NCTC 13129 genome is 2,488,625 bp in length and has an average G-C content of 53.5%. Corynebacterium diphtheriae is the bacterium that causes the disease diphtheria.Corynebacterium diphtheriae is a rod-shaped, Gram positive, non spore-forming, and nonmotile bacterium.