63. Genus Francisella.

Question 1

Francisella Habitat morphology and staining?

Answer 1

FRANCISELLA

1. Habitat: • rodents, blood sucking arthropods • environment, water
2. Morphology: • 0.5-2 µm coccoid rods, • thin capsule
3. Staining: • Gram-negative, • bipolar

Question 2

Culture

Answer 2

4. Culture:

• obligate aerobic • fastidious, • additives: • protein, • cystein, cystin, • yeast extract • media: • Francis-blood agar: • cystein – glucose – rabbit serum • cystein – glucose – egg yolk

Question 3

Biochemistry and antigens?

Answer 3

5. Biochemistry: • catalase +, • oxidase - • glycerol • +: F. tularensis subsp. tularensis • -: F. tularensis subsp. holarctica (palaearctica)

6. Antigens: • uniform, • cross reactions • Brucella spp. • Yersinia spp. • Pasteurella spp.

Question 4

Resistance and species?

Answer 4

7. Resistance: • weak • good survival in cold weather 8. Species: • F. tularensis subsp. tularensis: North America • F. tularensis subsp. holarctica (palaearctica): northern hemisphere • F. tularensis subsp. mediasiatica: Central Asia • F. tularensis subsp. novicida: sporadic USA, Asia

Question 5

Pathogenecity?

Answer 5

9. Pathogenicity: • facultative intacellular agent • tularaemia • wild living rodents • hare, • dog, cat, cattle, swine, sheep, • human (warfare agent)