Diphtheria Toxin

Diphtheria Toxin a potentially lethal infection mainly caused by toxigenic Corynebacterium diphtheriae strains. A similar illness could be produced occasionally by Corynebacterium ulcerans and rarely by Corynebacterium pseudotuberculosis strains. In general, the bacterium C. diphtheriae was found only in the upper respiratory tract of cattle, horses, and men. The first diphtheria epidemic occurred in Spain in 1613, and Pierre Bretonneau named the disease diphtheria in 1826. Edwin Klebs identified the causative bacterium in 1883, and Friedrich Löffler first cultured the pathogen and demonstrated exotoxin production in 1884. This bacterium acquired this toxic gene (tox) horizontally from 'corynephage' that d'Herelle first isolated from horse manure in 1918. A firmly adherent pseudomembrane formation in the throat is the usual characteristic symptoms of diphtheria due to acute respiratory infection, although coetaneous infections are possible. Diphtheria toxin causes systemic effects, such as neuropathy and myocarditis. This exotoxin is synthesized as a single polypeptide of molecular weight 62k Daltons. Cell death was caused due to inhibition of protein synthesis by this exotoxin. The causative pathogen, eg, Corynebacterium spp., was commonly isolated and identified by bacterial culture to confirm the clinical diagnosis. This diagnosis was followed by toxin detection and enzymatic tests. Diphtheria can be treated with diphtheria antitoxin and antimicrobial therapy with timely administration. Huge numbers of diphtheria cases are still reported yearly from various countries in Africa and Asia. Public health actions are required to prevent and control the spread of this disease. [AKM Mahbub Hasan]