Corynebacterium diphtheriae, Cause

Diphtheria is a bacterial respiratory infection characterized by membranous pharyngitis. The membrane may cover the pharynx, tonsillar areas, soft palate, and uvula. Diphtheria may also cause anal, cutaneous, vaginal, and conjunctival infections. The impact of diphtheria is not from the causative bacteria, Corynebacterium diphtheriae, but rather from complications attributed to its exotoxin, such as myocarditis and peripheral... 

The same factors that cause variations in the shape of bacteria also affect their size. With few exceptions, young cells are much larger than old or mature forms. Cells of B. subtilis from a 4-hr. culture measure five to seven times longer than cells from a 24-hr. culture. Variations in width are less pronounced. The organism Corynebacterium diphtheriae is a notable exception to the rule of decreasing cell size with age. 

Bacteria are both harmful and beneficial. They degrade the waste-products produced by society. They are used in wastewater treatment plants— thus, they are beneficial. On the other hand, they can also be pathogenic. The bacteria. Salmonella typhosa, causes typhoid fever Shigella flexneri causes bacillary dysentery. Clostridium tetani excretes toxins producing tetanus. Clostridium botulinum excretes the toxin causing botulism. Corynebacterium diphtheriae is the agent for diphtheria. 

Diphtheria toxin is the main pathogenicity factor in diphtheria (Pappen-heimer, 1977). The toxin gene is carried by a bacteriophage, p, which is lysogenic in Corynebacterium diphtheriae. Toxigenic strains of the bacteria cause local infection of the throat. After recovery from the acute phase of the disease, life-threatening organ complications often occur, mainly in the heart, which are due to toxin produced by the bacteria in the throat and released into the circulation. Due to mass vaccination, the disease is now almost extinct in developed countries. 

Corynebacterium diphtheriae Gram-positive rod, aerobe Causative agent of diphtheria... 

A-B Toxins are bacterial toxins composed of two peptide chains one (B) that binds to the invaded cell surface, and the other (A) containing the toxin which is then taken-up into the cell. Some examples of exotoxins secreted by the bacteria into the surrounding medium and highly toxic to certain tissues are pathogens causing botuiism (Clostridium botulinum), tetanus (Clostridium tetani) and diptheria (Corynebacterium diphtheria. An example of an A-B endotoxin is Vibrio cholerae. Botulinum toxin and tetanus toxin have their main toxic actions on neuronal tissues, so are described at NEUROTOXINS. 

One of the primary killers of children prior to immunization was upper respiratory tract infections by Corynebacterium diphtheriae. Toxin produced by a lysogenic phage that is carried by some strains of this bacteria causes the lethal effects. It is lethal in small amounts because it blocks protein synthesis. The viral toxin is composed of two parts. The B portion binds a cell s surface and injects the A portion into the cytosol of cells. The A portion ADP-ribosylates a histidine-derived residue of the elongation factor 2 (EF-2) known as diphthamide. This action completely blocks the ability of EF-2 to translocate the growing polypeptide chain. 

Other less common causes of acute pharyngitis include groups C and G Streptococcus, Corynebacterium diphtheriae. Neisseria gon-orrhoeae, M. pneumoniae, Arcanobacterium haemolyticum. Yersinia enterocolitica, and Chlamydia pneumoniae. Treatment options for these organisms will not be addressed in this chapter. ... 

Diphtheria is an acute illness caused by the toxin released by a Corynebacterium diphtheriae infection. The toxin inhibits cellular protein synthesis, with membranes forming on mucosal surfaces. Systemic toxemia can result in myocarditis, neuritis, and thrombocytopenia. Membrane formation can cause respiratory obstruction, and significant toxin absorption can lead to severe illness and death. 

There are dual infections where a disease is the result of a synergistic relationship between two microorganism species. Such relationships are both complex and more common than generally thought. A classic example of this is the human disease of diphtheria [6]. While the disease is caused by Corynebacterium diphtheriae, the toxin produced by this bacterium that accounts for its pathogenicity is due to lysogenic conversion of the C. diphtheriae by a specific bacterio-... 

Diphtheria A severe upper respiratory disease caused by Corynebacterium diphtheriae, can produce subsequent myocarditis and polyneuritis. 

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