47. Family Enterobacteriaceae (habitat, morphology, culture), genus Serratia

Question 1

Serratia Habitat, Culture and Pathogenicity?

Answer 1

SERRATIA
1. Habitat:
• soil, water
2. Culture:
• lower optimal temperature, pigment
3. Pathogenicity:
• saprophytes
• S. marcescens: food contamination

Question 2

Enterobacteriaceae habitat morphology and staining?

Answer 2

ENTEROBACTERIACEAE
• 40 genera
• > 180 species
1. Habitat:
• gut, mucous membranes
• normal gut flora
• environment
2. Morphology:
• 1-3 µm rod,
• flagella (except: Shigella, Klebsiella)
3. Staining:
• Gram-negative

Question 3

Culture 1?

Answer 3

Question 4

Culture 2?

Answer 4

4. Culture:
   • selective and differential media:
   • low selective capacity
   • enterobacteria
   • bacteria of some Gram-negative genera
   • medium selective capacity
   • some genera of Enterobacteriaceae
   • high selective capacity
   • salmonellae

Question 5

Culture 3?

Answer 5

4. Culture:
   • low selective capacity:
   • crystal violet – lactose - litmus (Drigalski)
   • crystal violet – bile salts – lactose – neutral red (MacConkey)
   • eosin – lactose – methylene blue – Na-lauryl sulphate
   • medium selective capacity:
   • brillant green – lactose – phenol red
   • deoxycholate-citrate – lactose – neutral red (DC)
   • XLD: xylose-lysine-deoxycholate – lactose – phenol red
   • high selective capacity:
   • bismuth-sulphite agar

Question 6

Culture 4?

Answer 6