Clostridium Perfringens
INTRODUCTION:
- Anaerobic
- Shows Stormy fermentation.
- The spores are usually wider than the rods
- Spores located terminally or sub terminally.
- Cl. perfringens is considered as an ideal bacteriological indicator as acceptability aspect of water
- Most clostridia are motile by peritrichous flagella.
MORPHOLOGY:
- Large Gram-positive bacilli
- Straight, parallel sides & slightly rounded ends.
- Measure 4-6×1μm in size,occuring singly or in chains
- Pleomorphic,capsulated & non-motile.
- Spores are rarely seen in culture media or material from pathogenic lesions, a characteristic morphologic feature
CULTURAL CHARACTERISTICS
- Robertson’s cooked meat broth is ideal;
- meat is turned pink but not digested with sour odor.
- Stormy fermentation of lactose in litmus milk; the acid coagulates casein-acid clot.
On BAM:
- Target haemolysis
BIOCHEMICAL REACTIONS:
|
Glucose Indole |
– |
|
Lactose Fermented with MR |
+ |
|
Maltose A & G production VP |
– |
|
H2S prodn. test |
+ |
|
Nitrate redn. test |
+ |
TOXINS:
12 distinct types of Preformed enterotoxins elaborated:
α toxin-
- lethal,dermonecrotic & hemolytic( principle toxin)
- Phospholipase C= lecithinase
- Associated with gas gangrene
- Shows Nagler reaction
- β,ε & ι toxins- lethal & necrotizing
- γ & η toxins- minor lethal action
- δ toxin-lethal & hemolytic for red cells
θ toxin-
- lethal & cytolytic
- Petfringolysin O.
- κ toxin- collagenase
- λ toxin-proteinase & gelatinase
- μ toxin- hyaluronidase & ν toxin-deoxyribonuclease
ENZYMES
- Neuraminidase
- destroys myxovirus receptors on red cells
- Hemagglutinin
- active against red cells of humans
- Fibrinolysin
- Hemolysin
- shows double zone of hemolysis
Lecithinase
- produce opacity around colonies
- by spliting lecithin into phosphorylcholine and diacylglycerol
- appear opalescence in serum or egg yolk media.
Bursting factor
- has specific action on muscle tissue
- responsible for muscle lesions in gas gangrene.
Circulatory factor-
- causes an increase in adrenaline sensitivity of capillary bed
- inhibits phagocytosis
Exam Question
INTRODUCTION:
- Shows Stormy fermentation.
- The spores are usually wider than the rods
- Spores located terminally or sub terminally.
- Cl. perfringens is considered as an ideal bacteriological indicator as acceptability aspect of water
- Spores are rarely seen in culture media or material from pathogenic lesions, a characteristic morphologic feature
TOXINS:
12 distinct types of Preformed enterotoxins elaborated:
α toxin-
- lethal,dermonecrotic & hemolytic( principle toxin)
- Phospholipase C= lecithinase
- Associated with gas gangrene
- Shows Nagler reaction
ENZYMES
- Hemolysin
- shows double zone of hemolysis
Lecithinase
- produce opacity around colonies
- by spliting lecithin into phosphorylcholine and diacylglycerol
- appear opalescence in serum or egg yolk media.
- Bursting factor
- Circulatory factor
Don’t Forget to Solve all the previous Year Question asked on Clostridium Perfringens