Corynebacterium Diphtheriae Disease

Corynebacterium Diphtheriae Disease

Corynebacterium diphtheriae is a causative agent of diphtheria.It is upper respiratory tract illness and it is a contageous disease.

1. Morphology

  • It is a Gram positive, non-motile, non spore forming bacteria.
  • Corynebacteria is non- capsulated slender rod.
  • It shows club shaped swelling and hence called as Corynebacteria.
  • Its size ranges from 3-6 μm in lenght and 0.6-0.8 μm in width.
  • These cells posses metachromatic granules.
  • Mode of multiplication is by binary fission.

2. Cultural characters

  • Corynebacterium can grow easily on ordinary media.
  • It growth is enhanced by addition of blood or serum in the media.
  • It grows in a temperature range of 15° C-40° C and optimum temperature for its growth is 36° C.
  • Neutral pH is optimum for its growth.
  • Corynebacteria diphtheriae may be aerobic or facultative anaerobic in nature.
  • They are fast growing organism.

3. Biochemical characters.

  • These cells has a capacity to ferment sugars like glucose, galactose and maltose and result in acid formation but no gas.
  • It is unable to ferment sugars like sucrose and lactose.
  • Urea hydrolysis test is observed as negative.

4. Pathogenecity.

  • Diphtheria bacilli is a exotoxin producing organism.
  • Diphtheria disease is caused due to exotoxin.
  • The site of infection may be nasal, faucial, laryngeal,and genital
  • These bacilli can cause circulatory failure,ulcer, hemorrhage, paralysis and diphtheria.

5. Laboratory diagnosis. 

  • Detection of diphtheria in initial stage is important for control of disease.
  • The laboratory diagnosis include collection of samples generally swab from the lesion are collected.
  • These samples are Gram stained for observation of Spirochetes.
  • Toxic diphtheria are identified by immunofluorescence technique.
  • These samples are isolated on blood agar.
  • After incubation the culture is used for granule staining for observation of metachromatic granule.
  • Virulence test such as subcutaneous test, Intracutaneous test, gel precipitation test and tissue culture technique is carried out.

6. Prophylaxis

  • Prophylaxis means prevention of disease.
  • Diphtheria can be easily controlled by immunization .
  • Active, passive, combined immunizations are available for prophylaxis.

7. Treatment.

  • Treatment of diphtheria include antibiotic and antitoxic therapy.
  • Antibiotic such as penicillin and erythromycin are effective drug againts diphtheria.
  • Antitoxin should be given as early as possible after detection of diphtheria.

8. Other pathogenic strain of Cornybacterium are-

  • Cornybacterium ulcerans.
  • Cornybacterium minutissimum.
  • Cornybacterium hofmanni.


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.