Clostridium Perfringens

Question 1

1) classification

Answer 1

Family: Clostridiaceae
Genus: Clostridium
Species: perfringens

• can be found in soil and dust
• On the basis of four exotoxins, C. Perfringens can be classified into six types: A, B, C, D, E and F

Question 2

2) morphology

Answer 2

Gram positive rods
Capsulated
Non motile
Spore forming
-spores situated terminally or sub-terminally
-spores are usually larger than the rods

Question 3

3) Growth characteristics

Answer 3

Anaerobic
Fastidious
Flesh eating

Question 4

4) antigenic structure

Answer 4

Capsular polysaccharide

Question 5

5) virulence factor

Answer 5

Spores
Alpha toxin (lecithinase)
Fibronolysin
Collagenase
Hyaluronidase
Hemomysin 
Hemagglutinin 

Spores-
Contaminated wound or through colon
Germinate at low oxidation-reducing potential; vegetative cells produce various types of toxins

Alpha toxin

• produced by all C.perfringens
• a necrotising hemolytic exotoxins that is also an alpha-lecithinase

Question 6

6) Disease

And clinical findings

Answer 6

Affects the muscles

Skin and Soft tissue infection:
CNN

Clostridium myonecrosis (gas gangrene)
Necrotic enteritis
Necrotic fasciitis
Suppurative infections and abscesses in uterus, Fallopian tubes, gall bladder and abdomen

Disseminated infection:
Clostridial Bacteremia
Severe sepsis
Food poisoning

Clinical finding

-pain
-oedema
-foul smelling discharge
- crepitation at wound site with rapidly progressive necrosis
- toxaemia
- fever
Death

Question 7

7) microbiological diagnosis

Answer 7

Direct microscopical examination

Gram-stain:
Large, relative short, fat, gram-positive rods with blunt ends and no spores

Absence of WBCs

Culture:

• inoculation in chopped-meat glucose and thioglycolate media and onto BAP to be incubated for 48 h at 37oC
• blood agar plate: Slightly raised colonies with double zone of beta hemolysis

Specific tests:

Lammy Will Not Run

Lecithinase test:

• egg yolk agar
• precipitate around colonies indicates lecithinase activity of the alpha toxins

William blear medium:

• cracks and bubbles (gas formation)
• Blackening (H2S production)

Nagler test:
- detected via lecithinase antitoxin which inhibits lecithinase reaction

Reverse CAMP test:
S.agalactiae exhibit enhanced haemolysis in the presence of C.perfringens - arrowhead appearance

Question 8

8) treatment and prevention

Answer 8

• surgical removal of infection
• penicillin
• hyperbaric oxygen may help

Prevention:

Early and adequate cleansing of wounds with administration of penicillin