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بسم الله الرحمن الرحيم. GENUS: CORYNEBACTERIUM Prof. Khalifa Sifaw Ghenghesh. Diptheroides = Coryneforms Gram +ve, Nonmotile Rods. Arranged in V forms or Palisades Catalase +ve. 1. Corynebacterium diphtheriae. Diphtheria. Pleomorphic Bacilli Cells Contain Metachromatic Granules.
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بسم الله الرحمن الرحيم GENUS: CORYNEBACTERIUM Prof. Khalifa Sifaw Ghenghesh
Diptheroides = Coryneforms • Gram +ve, • Nonmotile Rods. • Arranged in V forms or Palisades • Catalase +ve
1. Corynebacterium diphtheriae • Diphtheria. • Pleomorphic Bacilli • Cells Contain Metachromatic Granules. Morphology
Cultural Characteristics • i. Loeffler's Serum Slope. • ii. Tellurite BA. - Temp. 37oC, - Aerobic and Facultative AnO2.
Corynebacterium diphtheriae forms black colonies on tellurit agar (left), on blood agar colonies appear white (right)
PATHOGENICITY • Diphtheria is a Toxaemia. • Exotoxin: M. wt 62000 • 2 Fragaments >> A & B • Inhibits Protein Synthesis. • Has Special Affinity for Certain Tissues "Mycocardium, Adrenals, Nerve Endings". • Toxin >>Toxoid. • Site of Infection >>Faucial. • Toxin >>Pseudomemebrane.
LABORATORY DIAGNOSIS • Important>>Specific Treatment Should Be Started Immediately on Suspicion of Diphtheria. • Specimen:Two Swabs from the Lesion. • Culture: i. Loeffler's Serum Slope >> Albert Stain. ii. Tellurite BA. iii. BA>> Streptococcal or Staphylococcal Pharyngitis.
PATHOGENICITY TESTS • In-vivo Tests: i. Subcutaneous Test: ii. Intracutaneuos Test: • In-vitro Test: • Elek Test ( Gel Precipitaion Test). • Tissue Culture:
TREATMENT • i. Antitoxin:> Moderate Cases: > Severe Cases: • ii. Antibiotic: • i. Active Immunization >> PDT. • ii. Passive Immunization: • iii. Combined: PREVENTION
SCHICK TEST • > Injection of 0.2 ml of Diphtheria Toxin Intradermally. • > Positive Reaction >> Erythema + Swelling
SCHICK TEST ______________________________________________________________________ Result Test Arm Control Arm Interpretation Diphthri (Toxin) Inactivated Toxin Immunization 36h 120h 36h 120h ______________________________________________________________________ Negative -- -- -- -- Immune, Not Not Hypersensitive Required ---------------------------------------------------------------------------------------- Positive + + -- -- Not Immune, Not Required Hypersensitive --------------------------------------------------------------------------------------------------------------------- Negative + -- + -- Immune Not Hypersensitive Required --------------------------------------------------------------------------------------------------------------------- Positive& + + + -- Not ImmuneContra- PseudoHypersensitive indicated ______________________________________________________________________
بسم الله الرحمن الرحيم Listeria monocytogenes
Listerosis. • G+ve Coccobacilli >in Short Chains. • Motile at 25oC But Not at 37oC. • Aerobic to Microaerophilic. • On BA>Narrow Zone of b-Haemolysis. • Listerolysin O >
DISEASE • Incidence and Transmission > • i. In Adults: • ii. Neonatal Infections: a. Early Type: b. Late Type:
LABORATORY DIAGNOSIS • i. Specimen:Depend on Syndrome: Blood, CSF, Genital Tract Secretions. • ii. Media:Selective Media. • Penicillin, Ampicillin. TREATMENT
