Corynebacterium diphtheriae Characteristics Symptoms v Gram Positive bipolar
Corynebacterium diphtheriae Characteristics Symptoms v Gram – Positive, “bipolar staining” o Pseudomembranous pharyngitis v Shape – Bacillus, “club-shaped” o Grey-white exudative pharyngitis made of fibrin, v Motility – None granulocytes, necrotic epithelium, lymphocytes, and v Oxygen Requirements bacteria form the pseudomembrane on the pharynx. Will Facultative anaerobe bleed if scrapped. v Catalase – Positive o Caused by the Diphtheria Toxin v Oxidase - Positive o Might have cervical lymphadenopathy, and edema of the v Virulence Factors larynx giving a “bull’s neck” appearance this would v Diphtheria Toxin (DTX) cause stridor again v Is an A-B Toxin o Could cause myocarditis (20% of cases) when the toxin v The A subunit - ADP ribosylates kills myocytes elongation factor 2, inactivating it, and o Could cause polyneuritis (10% of cases) when the toxin causing a halt of all protein translation and kills the neurons eventual cell death v The B subunit - Binds to the receptors on Diagnosis host cells § Black colonies on Cysteine-Tellurite agar v The gene for this is carried on the “Beta § Can grown on Loeffler’s medium phage” which was a lysogenic transfer of § Often seen on Gram-staining as a “V” or palisades, or DNA and has integrated into the bacterial lying parallel to each other, but mostly look like chromosome. Not all strains have the maracas phage so not all are pathogenic Epidemiology and Risk Groups Ø Worldwide Transmission q Contaminated respiratory droplets q Can be a normal flora of the nasopharynx Treatment ü DTa. P Vaccine ü Toxoid vaccine for children under 6 ü Tdap Vaccine ü A reduced toxoid vaccine amount for people over 7 years old ü Diphtheria antitoxin ü A horse antibody intramuscular injection ü Erythromycin
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