CORYNEBACTERIUM DIPHTHERIAE

The meaning of Coryne is club . As diphtheria bacillus looks like club shaped , so it is called . The outer name of diphtheria bacillus is Klebs-Loeffler’s bacillus

Important members of Corynebacterim diphtheria

           1… Pathogenic

a)      Corynebacterium diphtheriae

b)      Corynebacterium ovis

c)      Corynebacterium murium

d)      Corynebacterium pyogenes

  2..  Non – pathogenic ( Dipththeroids ) –

  

a)      Corynebaterium xerosis

b)      Corynebacterium hofmanni

c)      Corynebacterium acnes.

Morphology

i)                    Shape – they are slender rods , straight or slightly curved rods .

ii)                   Size – They measures 3 to 5 μ in length and 0.5 to 1.0 μin breadth .

iii)                 Pleomorphism – Pleomorphism is frequently encounted , short forms and cells are swollen at one end , to represent club , swelling at the center or at both ends is frequently found . Meta chromatic granules may be present .

iv)                 Arrangements – Arrange singly or in groups , arranged at angels to each other resembling the letters L, V, Y , combination of these are likened for Chinese writing .

v)                  Degenerated an d disorted form may be present when culture is continued for more than 24 Hrs .

vi)                 Non-casulated .

vii)               Non-sporing .

viii)              Non-flagillated and non-motile .

ix)                 Gram positive bacteria .

Pathology produced by Corynebacterum diphtheria----

   Corynebacterium diphtheriae will produced diphtheriae . Infection with C. Diphtheriae occurs most commonly in the upper respiratory tract and causes sore throat . It is usually spread by droplet infection . The organim remain localized at the site of the infection from where soluble exotoxin is absorbed and damages the heart muscle and nervous system . The lesions of the nervous system is peripheral neuritis giving rise to paralysis involving mainly the palate , the limbs and accommodation of eyes . The infection may occur rarely on conjunctiva or the genital tract or it many ccomplicate wound abrasions or disease of the skin . the incubation period is two or four days . There types of C. diptheriae may be found like gravis , intermedius and mitis of which gravis and intermedius strains are associated with severe forms . in fatal cases , suprarenals of guineapig show gross macroscopical changes . Microscopically infiltration and minute haemorrhages may be found .