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Similar to عملي Corynebacterium-1 (Muhadharaty).ppt
عملي Corynebacterium-1 (Muhadharaty).ppt
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- 2. Gram positive rods Sporeforming Non spore forming Anaerobic Aerobic Clostridium spp Bacillus spp Corynebacterium Gram Positive Bacilli
- 3. Species of Corynebacteria Corynebacterium Pathogenic C.diphtheriae Commensal "Diphtheriods" C. hofmannii, C. xerosis, C. acne C. diphtheriae is the only pathogenic members of this genus It caused diphtheria Normal flora of RT, urethra, vagina, Skin
- 4. C. diphtheriae: Causative Agentof Diphtheria C. diphtheriae pseudomembran.
- 5. • Corynebacterium diphtheriaecan cause pharyngitis which leads to formation of thick grey membrane called pseudo-membrane. The pseudo-membrane is composed of fibrin, dead epithelial cells, bacteria and neutrophils. and then blocks the airway which results in suffocation. • As a result of the action of diphtheria toxin into blood stream it acts systemically affecting to peripheral motor neurons and myocardium, life-threatening systemic complications (principally loss of motor function and congestive heart failure) may develop. Pathogenicity
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- 7. Corynebacterium diphtheriae Gram positive Bacillidemonstrat pleomorphism( coccobacillary ), with characteristic morphology (club shaped and beaded) the beads are intracellular store of polymerized phosphate . They divided by ‘snapping fission’and hence are arranged angles to each other ,resembling (chinese characters ) Cell wall contain mycolic acid
- 8. Non motile Non sporeforming Non capsulated aerobic Breakdown glucose by oxidative and fermentative. C. diphtheriae is fastidious while diphtheriods are non-fastidious Catalase positive Oxidase negative
- 10. * Species :- C.Diphtheriae (diphtheria). Which contain 3 strains :- C. d. gravis C. d. mitis C. d. intermedius Non pathogen: C. hofmannii C. xerosis
- 11. Laboratory diagnosis 1 Stain –1-Gram stain: C. diphteriae are gram positive bacilli arranged in Chinese letters form often club shaped – 2-Neisser methylene blue stain: C. diphteriae appears beaded due to the presence of intercellular “Metachromatic " granules By stain, the granules appear red while the rest of organism appears blue. -3- Albert stain dark purple by Albert staining method.
- 12. Gram stain of C.diphtheriae Neissermethylene blue stain metachromatic granules Albert stain
- 13. (Specimen: A throatswab) – 2 Culture:. 1- On Loeffler's serum medium: Corynebacteria grow much more easily than other respiratory pathogens –Used to enhance the characteristic microscopical appearance of corynebacteria –The colonies of C. diphtheriae are small, granular, grey, smooth, and creamy with irregular edges Loefflers serum
- 14. 2- On bloodtellurite agar. – It is selective medium for isolation of C. diphtheriae (Potassium tellurite) – 3 biotypes of C. diphtheriae are characterized on BTA – i.e. Gravis, mitis and intermedius biotypes – The most severe disease is associated with the gravis biotype – Colony of gravis biotype → 3mm . Radical form, Raised center. – Colonies of mitis biotype are 2.4 mm, small, hemolytic and black – Colonies of intemedius biotype are 1-2 mm, intermediate in size, non-hemolytic with black center & grey margin.
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- 16. 3-Biochemical Reaction Catalase (+) Oxidase(-) Gelatinase (-) Urease (-) Phosphatase (-)
- 17. Table indentification ofCorynebacterium strains H2S Urease Starch Sucrose Glucose Catalase M.O + - - - - - + - - - - - + + + + + + C. d. gravis C. d. intermedias C. d. mitis
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- 19. Detection of exotoxin I-In vivo II- In vitro Two guinea pigs are used One is used as Test The second is used as Control Injected with diphtheria antitoxin Both test and control injected with isolated MO If both GP live If control live & test die Diphthrioids 0r non-toxigenic C. diphtheriae i.e. non pathogenic C. diphtheriae i.e. produce exotoxin •If both the test and control show illness or die= It is another organism.
- 20. In Vitro: Elek’sTest Principle: – It is toxin/antitoxin reaction – Toxin production by C.diphtheriae can be demonstrated by a precipitation between exotoxin and diphtheria antitoxin Procedure: A strip of filter paper impregnated with diphtheria antitoxin is placed on the surface of serum agar The organism is streaked at angels to the filter paper Incubate the plate at 37C for 24-48 hrs.
- 21. Resuls: After 48 hrsincubation, the antitoxin diffusing from filter paper strip and the toxigenic strains produce exotoxin, which diffuses and resulted in lines four precipitation lines radiating from interaction of the strip and the growth of organism Filter paper saturated with diphtheria antitoxin Inoculated M.O. Positive Elek’s Test Lines of precipitations
- 22. 22 abed elkaderelottol
- 23. Non pathogen CorynebacteriaeSpp. * Diphtheriods :- • Bacilli that morphology resemble diphtheria. • It is not pathogenic. • It is found on skin or conjunctiva and oral cavity. • It is opportunistic pathogens. • It is short 1-5µm with parallel sides and rounded ends without metachromatic granules. • Actual differentiation can be made out by biochemical testes and virulence test .
- 25. Diphtheroids Diphtheria G+ , shortand thick Absence Grow on ordinary media Fermentation of glucose , sucrose Usually non toxic positive A- morphology G+ and thin meta chromatic granules B- culture Grow on enrich media C- biochemical test Fermentation of glucose D- Toxogenicity they are toxic E- Urease test negative
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