49. Genus Escherichia.

Question 1

Habitat Morphology and staining?

Answer 1

ESCHERICHIA
E. coli
1. Habitat:
• gut,
• aerobic, facultative anaerobic gut flora
2. Morphology:
• 2-3 µm rod,
• capsule,
• flagella,
• fimbria
3. Staining
• Gram-negative

Question 2

Culture?

Answer 2

4. Culture:
   • simple, not fastidious
   • following the general principles of Enterobacteriaceae
   • selective and differential media
   • grows on low and medium selective media
   • capsule
   • E. coli strains from calf
   • haemolysis
   • E. coli strains from swine

Question 3

Biochemistry?

Answer 3

Indol +

Lactose +

Question 4

Biochemical characteristics?

Answer 4

Question 5

Antigens and Resistance?

Answer 5

6. Antigens:
• O: type specific (187 types)
• K: polysaccharide (60 types)
• F: 30 types
• F1: common fimbria
• F2, F3: human
• F4 (K88), F6 (987p), F18 ab/ac: swine
• F5 (K99), F17, F41: cattle
• F7-F16: UTI (urinary tract infection): human, poultry
• H: 53 types
7. Resistance:
• medium

Question 6

Pathogenecity?

Answer 6

8. Patogenicity
   • saprophyte
   • normal gut flora
   • normal flora of mucous membranes
   • facultative pathogenic
   • cattle
   • swine
   • sheep, goat
   • rabbit
   • poultry
   • foal, dog, cat, mink, fox, nutria, chinchilla
   • human
   • genetic variety

Question 7

Pathogenecity 2?

Answer 7

8. Pathogenicity:
   • cattle
   • calf coli-diarrhoea (neonatal)
   • calf coli-septicaemia
   • cow: mastitis
   • swine
   • coli-diarrhoea of neonatal piglets
   • weaned piglets: coli-diarrhoea
   • weaned piglets: oedema disease
   • sow: mastitis, metritis
   • lamb, kid:
   • coli-diarrhoea (neonatal), watery mouth
   • rabbit:
   • diarrhoea

Question 8

Pathogenecity 3?

Answer 8

Pathogenicity:
• poultry:
• day-old-chicken: septicaemia
• chicken: septicaemia, respiratory disease
• adult: lesions in organs
• airsacculitis, peritonitis, coli-granulomatosis
• foal, dog, cat, mink, fox, nutria, chinchilla:
• coli-diarrhoea, septicaemia
• human:
• neonatal enteritis, septicaemia,
• urogenital infections,
• enteritis,
• haemorrhagic enterocolitis, haemolytic uraemic syndrome

Question 9

Groups of pathogenic e coli strains?

Answer 9

9. Groups of pathogenic E. coli strains (pathotypes)
   • enteropathogenic strains
   • enterotoxigenic strains
   • verotoxigenic strains
   • necrotoxic (cytotoxic necrotic factor producing) strains
   • enteroinvasive strains (human): like Shigella
   • enteroadhesive-aggregative strains (human)
   • septicaemic strains

Question 10

Virulence factors of the pathogenic e coli strain 1?

Answer 10

Virulence factors of the pathogenic E. coli strains
• enteropathogenic strains
• intimin
• damage of enterocytes and microvilli
• enterotoxigenic strains
• adhesive factors
• fimbria
• surface proteins
• enterotoxins
• LT ( heat labile) toxin: protein (88.000 D)
• ST (heat stabile) toxin: polypeptide (1.500-2.000 D)
• damage of fluid absorption

Question 11

Virulence factors of the pathogenic e coli strains 2?

Answer 11

9. Virulence factors of the pathogenic E. coli strains
   • verotoxigenic strains
   • verotoxins (shiga-like toxins)
   • VT1 (Stx1), VT2 (Stx2)
   • damage of endothelial cells
   • necrotoxic (cytotoxic necrotic factor producing) strains
   • cytotoxic necrotic factor (CNF)
   • enteroinvasive strains
   • human, dysentery, like Shigella
   • enteroadhesive-aggregative strains (human)
   • septicaemic strains
   • invasiveness
   • survival in blood