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8 terms

CLOSTRIDIUM -Colony Morphology

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C.botulinum /sporogenes
Large (3 mm)
irregularly circular
smooth
greyish
translucent with a fibrillar edge
β-haemolytic
produces lipase
C.difficile
Glossy
grey
circular colonies with a rough edge
fluoresce green-yellow under UV light
non-haemolytic
characteristic farmyard smell.
Cl.novyi
Raised
circular colonies
become flattened and irregular in old cultures.
Colonies tend to fuse
form spreading growth with a double zone of β- haemolysis.
produces lecithinase and lipase
Cl.perrfringens
Large
smooth
regular convex colonies
may be rough and flat with an irregular edge
has a double zone of β-haemolysis
produces lecithinase
Cl.septicum
thick swarming growth
narrow zone of β-haemolysis
Cl. Sorderans/bifermentelli
Grey-white
convex
circular colonies with crenated edges
which may spread
may be β-haemolytic
produce lecithinase
indole positive
Cl. tetani
Fine swarming growth (difficult to see)
may appear β-haemolytic
Other clostridium species
Colonial appearances vary
produce a spreading growth
may or may not be β-haemolytic