IA. General Microbiology | 16. Non-toxic virulence factors of bacteria.

Question 1

What are Non-toxic virulence factors?

Answer 1

substances on the surface and extracellular enzymes

Question 2

I. Surface structures
1. What are the surface structures acting asNon-toxic virulence factors?

Answer 2

• Capsule
• Pili, fimbriae (e.g. E. coli)
• Adhesins (e.g. B. pertussis)
• F protein (fibronectin binding, S. pyogenes)
• Protein A (IgG binding, S. aureus)
• Lipoteichoic acid (S. pyogenes)
• Invasins (provoked phagocytosis, e.g. Listeria)

Question 3

I. Surface structures
2. What is the role of surface structures?

Answer 3

help in adhesion, mimicri, and avoid phagocytosis

Question 4

I. Surface structures
3A. What are the features of capsule as non-toxic virulence factor?

Answer 4

Capsule → provides physical protection
- Helpful in avoiding phagocytosis, mechanical
defense, attachment to surfaces
- Made of polysaccharides, except in B. anthracis (poly-D-glutamic acid) and S.pyogenes (hyaluronic acid)
- Seen in: H. influenzae, Streptococcus pneumonia, Str. agalactiae, Neisseria meningitidis, E.coli, Bacillus anthracis

Question 5

I. Surface structures
3B. What is the capsule made of?

Answer 5

Made of polusaccharides, except in B. anthracis (poly-D-glutamic acid) and S.pyogenes (hyaluronic acid)

Question 6

I. Surface structures
3C. Where can you see capsule?

Answer 6

Seen in: H. influenzae, Streptococcus pneumonia, Str. agalactiae, Neisseria meningitidis, E.coli, Bacillus anthracis

Question 7

I. Surface structures
4. Give example(s) of bacteria that have Pili, fimbriae

Answer 7

E. coli

Question 8

I. Surface structures
5. Give example(s) of bacteria that have Adhesins

Answer 8

B. pertussis

Question 9

I. Surface structures
6. Give example(s) of bacteria that have F protein

Answer 9

fibronectin binding, S. pyogenes

Question 10

I. Surface structures
7. Give example(s) of bacteria that have Protein A

Answer 10

IgG binding, S. aureus

Question 11

I. Surface structures
8. Give example(s) of bacteria that have Lipoteichoic acid

Answer 11

S. pyogenes

Question 12

I. Surface structures
9. Give example(s) of bacteria that have Invasins

Answer 12

provoked phagocytosis, e.g. Listeria

Question 13

II. Enzymes
1. What is the role of enzymes as non-toxic virulence factor?

Answer 13

• For invasion and degradation
• To avoid host defense (antiphagocytic)

Question 14

II. Enzymes
2. What are the enzymes participating in invasion and degradation?

Answer 14

• Hyaluronidase, collagenase (penetrate deeper into skin), elastase, phospholipase, fibrinolysin
• Proteases, DNAse, RNAse, streptodornase, lecithinase, hemolysins

Question 15

II. Enzymes
3. What are the enzymes participating in avoiding host defense (antiphagocytic)?

Answer 15

• Coagulase, IgA protease, leukocidin (can lyse leukocytes)