Corynebacterium
Last reviewed 01/2018
Corynebacterium is a genus of bacteria, of which the most important is C.diphtheriae, which causes diphtheria.
Pathogenic C. diphtheriae is differentiated from non-pathogenic 'diphtheroids' by:
- pathogenicity tests in vivo
- toxogenicity tests in vitro
- biochemical tests:
- pathogens generally cannot ferment sucrose or hydrolyse urea
- C. ulcerans, a pathogen, is an exception in that it can hydrolyse urea
- cultivation:
- diphtheroids:
- are more regular in appearance
- tend to grow side-by-side
- tend to form black colonies with tellurite medium
- C. diphtheriae:
- show pleomorphism of form
- are irregularly orientated with respect to each other
- exhibit metachromatic granules
- tend to form dark grey colonies with tellurite medium
Generic properties are detailed in the submenu.