31.Bacillus anthracis

Question 1

B.anthracis Habitat, Morphology and staining?

Answer 1

B. anthracis
1. Habitat: animals (vegetative), environment (spore)
2. Morphology: 4-5 µm rod, central spore, capsule, no
flagella
3. Staining: Gram-positive, toluidine-blue
(metachromatic staining: capsule-pink, bact.-blue )

Question 2

Culture?

Answer 2

4. Culture

: simple (nutrient broth or agar, blood agar, air, 37°C)
R-S colonies (depends on CO2)
capsule: poly-D-glutamic acid (virulence factor –
inhibits phagocytosis), plasmid encoded
spore – for spore formation: - at least 15 °C
- water
- oxygen
- cations are needed
do not open the carcass!!!
Time which is needed:
- 37 °C: finished within 16 hours
- 18 °C: it will started after 50 hours! (2-3 days are needed)

Question 3

Biochemistry and Antigens?

Answer 3

5. Biochemistry: active metabolism, catalase +, oxidase -
6. Antigens: •capsule (poly-D-glutamic acid) - saprophytes!

•polysaccharide hapten: cell wall heat stabile, Ascoli test,
B. cereus – cross reaction!

•oedema factor •lethal factor •protective antigen
Toxin! (plasmid encoded)

Question 4

Resistance?

Answer 4

7. Resistance: •vegetative bacterium: several days in a carcass,
   skin: 2 weeks, bone marrow: 4 weeks, 56°C: 15 min
   •spore (in the soil can survive for more than 50 years!!!),
   boiling: 5-10 min, formalin (8-10%): 12-24 h

Question 5

Pathogenecity?

Answer 5

8. Pathogenicity: mammals (mainly herbivorous animals)

• Cattle, sheep: fatal peracut or acut septicaemic anthrax

• *• Pigs:** - subacute anthrax with oedematous swelling in pharyngeal region
• *• Horses:** - subacute anthrax with localised oedema
• septicaemia with colic and enteritis

• Humans: skin-, pulmonary and intestinal forms • Carnivores are comparatively resistant, birds are totally resistant
Dissection =
help for B. a.
in sporulation!!!