Corynebacterium diphtheriae infection

Diphtheria toxin, an exotoxin of Corynebacterium diphtheriae infected with a specific lysogenic phage, catalyzes the ADP-ribosylation of EF-2 on the unique amino acid diphthamide in mammalian cells. This modification inactivates EF-2 and thereby specifically inhibits mammalian protein synthesis. Many animals (eg, mice) are resistant to diphtheria toxin. This resistance is due to inability of diphtheria toxin to cross the cell membrane rather than to insensitivity of mouse EF-2 to diphtheria toxin-catalyzed ADP-ribosylation by NAD. 

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. 

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... 

Although erythromycin is a well-established antibiotic, there are relatively few primary indications for its use. These indications include the treatment of Mycoplasma pneumoniae infections, eradication of Corynebacterium diphtheriae from pharyngeal carriers, the early preparox-ysmal stage of pertussis, chlamydial infections, and more recently, the treatment of Legionnaires disease, Campylobacter enteritis, and chlamydial conjunctivitis, and the prevention of secondary pneumonia in neonates. 

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. 

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. 

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-... 

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