Corynebacterium .

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Corynebacterium. Corynebacterium. Classification Corynebacterium  diphtheriae  and diphtheroids (look  like   C. diphtheriae )  are  Gram- positive, club  shaped  rods.   Some  are saprophytic Some   produce  disease   in   animals.  
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Corynebacterium Classification Corynebacterium  diphtheriae  and diphtheroids (look  like   C. diphtheriae )  are  Gram- positive, club  shaped  rods. Some  are saprophytic Some   produce  disease   in   animals. C. diphtheriae is the most vital pathogen in the gathering. Morphology and social attributes Small G+B; arrangement=palisade or Chinese letters Growth on B.A – raised, translucent, dark colonies 

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Diphtheroids Gram recolor

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Arrangement of C. diphtheria

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Corynebacterium Loeffler\'s agar slant­ contains serum and egg that upgrade the  formation  of metachromatic  granules (polymerized polyphosphoric corrosive) in C. diphtheriae . Likewise called Babes-Ernst granules. They  are imagined  by  staining  with methylene blue.

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Methylene blue stain from Loefflers incline

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Corynebacterium A medium containing tellurite ought to be utilized to choose for Corynebacterium  and  other G+  organisms - it  inhibits  G­ life forms. Two sorts are utilized: Cystine tellurite ­ has a more extended  shelf  life Tinsdale ­ helps  to  differentiate amongst the Corynebacterium . Colonies on  either  appear dark  or dim because of tellurite lessening. S. aureus  and Listeria  also grow as dark settlements. On  Tinsdale   C. diphtheriae,  ulcerans, and pseudotuberculosis  form  brown coronas around the states because of arrangement of ferric sulfide.

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Corynebacterium 3 morphological  types of C. diphtheriae are  found on tellurite containing media: Mitis – dark provinces with a dim  periphery Gravis – substantial,  gray  colonies Intermedius – little, dull gray  to dark. All create an immunologically indistinguishable poison. Brooding - 35-37 0 C for 24 hours. They lean toward a pH of 7.8-8.0 for good development. They oblige access to oxygen (poor AnO 2 development). Organic chemistry Catalase +

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Corynebacterium Nonmotile C. ulcerans is urease +, C. diphtheriae is - , and C. pseudotuberculosis is typically + Virulence factors­ C. diphtheriae For C. diphtherias to bring about diphtheria an exotoxin must be  produced. Is a warmth labile polypeptide created amid lysogeny of  a  phage that conveys the "tox" quality. Basic pH of  7.8-8.0, vigorous conditions, and a low natural iron level are vital for poison creation (happens late in the development of the life form). The  toxin  inhibits protein  synthesis  by  ADP-ribosylating lengthening element  2. What other living being produces a comparative toxin? 

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Corynebacterium Trypsin  cleaves  the poison into 2 sections, An and B, that are linked together by a disulfide connect. Piece B is required for poison  binding to tissue cells and section A contains  the poisonous action. One particle of poison can repress  90%  of the  protein blend in a cell. Systemic impacts  include heart disappointment, loss of motion and adrenal hypofunction prompting an Addison resembles malady. C. ulcerans and C. pseudotuberculosis once in a while make a diphtheria-like  toxin.

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C. diphtheria poison Toxin enters through receptor interceded endocytosis Acidification of endocytic vesicle permits A to separate from B An enters cycoplasm

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C. diphtheria poison

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Corynebacterium To prove  that a detach can bring about diphtheria, one  must show  toxin  production. This is frequently done  on  an  Elek plate: The  organism is streaked on a plate containing low iron. A channel strip containing neutralizing agent poison neutralizer is set opposite to the dash of the life form. Dispersion of the immunizer into the medium and emission of the poison into the medium happen. At the zone of identicalness, a hasten will shape.

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Elek plate

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Corynebacterium Guinea pig or tissue culture poisonous quality examines may likewise be finished. Case – is protein in nature Cord calculate – is a complex glycolipid (trehalose 6,6\'- dicorynemycolate) that has been appeared to disturb mouse mitochondria. It has not been appeared to assume a part in the creation of diphtheria.

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Corynebacterium Clinical Significance ( C. diphtheria ) Is typically found in the throats  of  healthy transporters. The creature contaminates just man and it has a restricted ability to attack. Diphtheria -  Disease typically begins as a neighborhood contamination of the  mucous films bringing about a membranous  pharyngitis Local  toxin  effects result  in degeneration of epithelial cells. Irritation, edema, and creation of a pseudomembrane made out of fibrin clots, leukocytes,  and dead epithelial cells and microorganisms happens  in  the throat.

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Diphtheria - pseudomembrane This may block the  airway  and result  in suffocation.

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Corynebacterium The more perilous  effects  occur when the poison gets to be systemic and  attacks the  heart (heart disappointment),  peripheral nerves (loss of motion), and the adrenal organs (hypofunction). Cutaneous  diphtheria­  More  common  in tropical and subtropical zones. Necrotic injuries with periodic development of a neighborhood pseudomembrane happen. Anti-toxin weakness and treatment Antiserum ­ once the poison has bound, in any case, the antiserum  against it is inadequate. Penicillin­ to wipe out the living being.

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Corynebacterium Prevention-Active vaccination with toxoid (alum accelerate). Is a piece of the DPT antibody. Shick skin test­ like the Dick test in that it  tests  for circling  antibody  to the poison by infusing a little sum  of  toxin intradermally and watching for  a  local erythematous  and  necrotic response. In the event that this occurs it demonstrates  that  the individual has no immunizing agent poison  antibodies  and  is, consequently, defenseless to diphtheria. Other Corynebacterium­ are a piece of the ordinary greenery of  the skin and URT.

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Corynebacterium Are called diphtheroids and may sometimes bring about malady, especially in immunocompromised people. C. ulcerans ­  toxigenic strains  may  produce  a  disease like, yet less serious than diphtheria. J-K Group­  commonly  cause  infections  in  those   with underlying disease.   Diseases incorporate bacteremia, meningitis, peritonitis, wound contaminations, and so forth. It  is turning out to be increasingly of an issue. C. pseudotuberculosis ­ found in those with presentation to creatures. Can bring about pneumonia or lymphadenitis. Produces an alternate exotoxin than C. diphtheriae .

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