Lecture 7: Virulence in Bacteria

Question 1

Free living bacteria

Answer 1

No importance for animals and disease

Question 2

Symbionts

Answer 2

Living together

Question 3

Two types of symbionts

Answer 3

Obligate - need host

Facultative

Question 4

Mutualism

Answer 4

Both are necessary and relation is positive for both

Question 5

Commensalism

Answer 5

Good for one, no problem for the other (ex. intestinal flora)

Question 6

Parasitism

Answer 6

One takes advantage of the other

Question 7

Balanced pathogenicity

Answer 7

Damage with recovery

Question 8

Unbalanced pathogenicity

Answer 8

High damage/death

Question 9

Infection

Answer 9

Invasion and multiplication of micro-organism, eventually with disease

Question 10

How do some cells create adhesion

Answer 10

• Flagella

- Pili, fimbria, and fibrillae

Question 11

What are flagella composed of?

Answer 11

flagellin

Question 12

Where are flagella normally found?

Answer 12

gram negative bacteria

Question 13

Special pili

Answer 13

Sex pili

Bacteria conjugation

Question 14

Extracellular invasion

Answer 14

• Thromboses, local use of nutrients/oxygen

- Immunological reaction: oxygen radicals/enzymes by macrophages and neutrophils

Question 15

4 virulence factors involved

Answer 15

• Capsule
• Proteins that circumvent innate immunity
• Production of extracellular enzymes

Question 16

Capsule

Answer 16

• Not in all bacteria
• Polysaccharides (proteins)
• Protects against phagocytosis and the environment
• Capsular antigens (K)

Question 17

Exotoxins

Answer 17

• Bacterial metabolites

- Proteins with high molecular weight

Question 18

Type 1 exotoxins

Answer 18

• Bind receptor

- Disturb cell metabolism

Question 19

Type 2 exotoxins

Answer 19

-Cell wall damage

Question 20

Type 3 exotoxins

Answer 20

• Intracellular toxins
• A component goes IC
• B component binds membrane

Question 21

Endotoxin

Answer 21

• Cell wall components

- Heat stable (LPS)

Question 22

Functions of LPS

Answer 22

• Protects against toxic products

- Acts as an endotoxin

Question 23

Roles of membrane vesicles (7)

Answer 23

1. Pathogenesis
2. Signaling
3. Excretion of toxic products
4. Killing of competitors
5. Immunomodulation
6. Excretion of bacterial toxic products
7. Transformation

Question 24

Composition of biofilms

Answer 24

polysaccharides
proteins
nucleic acid

Question 25

Role of lipoproteins (outer membrane)

Answer 25

Adhesion

Iron uptake

Question 26

Two main types of vaccines

Answer 26

• Attenuated

- Non-living organisms

Question 27

Two types of Non-living organism vaccines

Answer 27

• DNA

- Based on antigen

Question 28

Three types of vaccines based on antigens

Answer 28

• Toxoid (inactivated exotoxin)
• Bacterins (inactivated complete bacteria)
• Subunit vaccines