33. Genus Clostridium (habitat, morphology, culture). Clostridium species causing gas gangrene diseases.

Question 1

Clostridum Key points?

Answer 1

genus CLOSTRIDIUM
Key points:
- more than 230 species
- large Gram-positive rods
- endospores produced
- obligate anaerobic
- catalase- and oxidase-negative
- motile (except C. perfringens)
- enriched media are required
- present in soil, in alimentary tract of animals and in faeces
- pathogens can be grouped according to the mode and sites of action of their
potent exotoxins:
- neurotoxic clostridia
- histotoxic clostridia
- enteropathogenic and enterotoxaemia producing clostridia

Question 2

Habitat, Morphology Staining and culture?

Answer 2

CLOSTRIDIUM
1. Habitat: soil, mud, water, gut
2. Morphology: 7-10 µm rod, flagella (exc. C. perfr.),
Spore (terminal, subterminal, central), no capsule (exc. C. perfr.)
3. Staining: Gram-positive
4. Culture: • anaerobic, oxygen tolerance different (C. tetani, C. novyi B:
strict anaerobic)
(C. histolyticum, C. botulinum: can tolerate O2)

• Nutrient agar, Blood agar

• optimal temperature:• 37 oC
• 40-45 oC C. perfringens

• 15-22 oC C. putrefaciens

Question 3

Pathogenic Clostridium species of veterinary importance

Answer 3

Question 4

List the gas gangrenic disease?

Answer 4

gas gangrenic diseases

• malignant oedema (cattle, pig, sheep)
• C. septicum
• C. novyi
• C. haemolyticum
• C. histolyticum
• C. sordellii
• Blackleg (cattle, sheep) •C. chauvoei
• human gas gangrene
• C. perfringens A
• C. novyi A

Question 5

C.septicum?

Answer 5

C. septicum
• culture: nutrient agar
• toxins: alpha (haemolytic, necrotic, lethal), DN-ase,
hialuronidase, haemolysin
• disease: malignant oedema in cattle pig and sheep
bradsot (abomasitis in sheep and calves, braxy)

Question 6

C.noyvi and C. haemolyticum

Answer 6

C. novyi •

Toxins:alpha, lipase, lecitinase, DN-ase, collagenase
•types: A, B, C (non pathogenic, no toxins)

•diseases: •gas gangrene: Cl. novyi A/B
•infectious necrotic hepatitis of sheep (and cattle): Cl. novyi B
C. haemolyticum
•bacillary haemoglobinuria of cattle (and sheep)

Question 7

C.histolyticum and .chauvoei?

Answer 7

C. histolyticum
•wide spread, can tolarate O2
•toxins: alpha, collagenase, protease, elastase, haemolysin
•Disease: malignant oedema cattle, pig, sheep
C. chauvoei •culture: blood agar, strong haemolysis, only guinea-pig suscept.! •toxins: as C. septicum
•disease: blackleg in cattle and sheep
•differentiation from C. septicum: •culture •IF •animal trial •toxin neutralisation

Question 8

C.perfringens?

Answer 8

C. perfringens
•optimal temperature: 40- 45 o
C, no flagella,
have a capsule
•toxins: - main (alpha, beta, epsilon, iota – activated by
trypsin)
- auxiliary toxins (gamma, delta, theta, kappa,
lambda, mü), neutralisation

Question 9

C.perfringens type 2?

Answer 9

Question 10

C.colinum and C.difficile?

Answer 10

• C. colinum
quail, chicken, turkey, pheasant: ulcerative
enteritis: intestinal ulceration, hepatic necrosis
• C. difficile
enterotoxin, cytotoxin
human: pseudomembranaceus colitis
foal: haemorrhagic enterocolitis in newborn
foals
dog: chronic diarrhoea