Pathogenesis

Question 1

Pathogen

Answer 1

microbe causes disease

Question 2

Pathogenicity

Answer 2

ability of a microorganism cause disease to other organism

Question 3

Opportunistic pathogen

Answer 3

cause disease by accessing to tissue or body sites where they are not usually found

Question 4

True pathogen

Answer 4

cause disease by producing toxin or damaging compound

Question 5

Virulence

Answer 5

Measurement of pathogenicity

High virulent, more likely to cause disease

Question 6

Indicators of virulence

Answer 6

Median infectious dose (ID50)

Median lethal dose (LD50)

Question 7

Median infectious does (ID50)

Answer 7

number of pathogen cells required to activate infection in 50% of inoculated animals

Question 8

Median lethal dose (LD50)

Answer 8

number of pathogen cells required to kill 50% of infected animals

Question 9

Steps of pathogenesis

Answer 9

1. Entry: with number of invading microbes + adherence
2. Penetration or Evasion of Host Defenses
3. Damage Host cell
4. Exit: usually same with entrance

Question 10

Factors of virulence

Answer 10

Adhesion
Colonization
Toxigenesis
Invasiveness
Resistance and immune system evasion

Question 11

Adhesion

Answer 11

Process that bacteria attach to cell, tissue, and biological subtances

Question 12

Colonization

Answer 12

adherence, multiplication, and establishment of bacteria at entrance

Question 13

Toxigenesis

Answer 13

ability to produce toxins

Question 14

Invasiveness

Answer 14

ability to forcingly enter tissues

Question 15

Resistance and immune system evasion

Answer 15

ability of bacteria to resist antimicrobial compounds or to escape containment of host immune system

Question 16

Steps of immune system

Answer 16

1. Innate immunity: rapid, halts infection, no memory

2. Adaptive immunity: slower, clears infection, memory

Question 17

Antigen

Answer 17

Foreign particle elicit immune response

Question 18

Epitope

Answer 18

A segment of antigen where antibody recognize and bind to.

Question 19

How antibodies work?

Answer 19

Neutralization
Opsonization
Complement activation

Question 20

Neutralization

Answer 20

Antibodies bind their target

Question 21

Opsonization

Answer 21

Macrophage or neutrophil consume the target. When enough bacterial cells, antibodies will conjugate and form polymers to stick large amount of pathogen to prevent them from getting away and to localize them

Question 22

Complement activation

Answer 22

Series of protein damages microbe

Question 23

How are microbes digested?

Answer 23

1. Phagosomes cover microbes.
2. H+ pumps on phagosomes surface pump into phagosome mixture
3. Lysosomes are activated by low pH and digest microbes.

Question 24

Ways of invasion

Answer 24

Injecting multiple protein into host cell to disrupt, kill, or make the cell work differently.
Causing cytoskeletal reorganization which engulf the bacteria.
Disrupting intercellular attachment molecules.
Using surface protein to bind to host cell surface and induce its own endocytosis

Question 25

How pathogen can survive from being digested?

Answer 25

Block lysosome

Stop the digestion by inhibiting enzyme or producing opposite phasing proton

Question 26

Compare types of toxin

Answer 26

Lipopolysaccharides (LPSs): endotoxin
Proteins:
- Tissue sites
- Extracellular diffusible toxins
- Heat-labile

Question 27

What include in the production of inflammatory cytokines?

Answer 27

Tumor necrosis factor (TNF)
Interleukin-1Beta (IL-1Beta)
Gamma interferon (IFNy)
Chemokines

Question 28

What happen with overzealous production of inflammatory cytokines?

Answer 28

Lead to cytokine storm

Contribute to mortality consecutive to sepsis or toxic shock syndrome

Question 29

What the production of inflammatory of cytokines do?

Answer 29

Guide anti-infectious innate immune response

Question 30

Endotoxin

Answer 30

• Inflammatory bc they auto-amplificatory loops after monocytes activate
• Cell wall of Gram-negative
• Heat-stable

Question 31

Why endotoxin is the most potent microbial mediator?

Answer 31

• Small does within a localized tissue space can make antimicrobial defense and stimulate bacterial clearance mechanism.
• Sudden release of large amount can release a massive, dysregulated, and potentially lethal inflammatory response such as endothelial injury, low blood flow, disseminated intravascular coagulation, low blood pressure

Question 32

Exotoxin

Answer 32

• Gram-positive

- Cell lysis

Question 33

How exotoxin work?

Answer 33

1. Bacterium produces and release exotoxin
2. B component binds host cell receptor
3. A-B exotoxin enters host cell by endocytosis
4. A-B exotoxin close pinched-off potion of plasma membrane during pinocytosis
5. A-B exotoxin separate. A component inhibit protein synthesis and affect cell function. B component release from host cell

Question 34

A-B exotoxin (binary toxin)

Answer 34

• 2-component protein complex secreted by pathogenic bacteria
• Comprise of heavy and light chain
• Connect by disulfide bond
• Ex: botulinum toxin

Question 35

How botulinum toxin affect nerve cell function?

Answer 35

• Flaccid paralysis: neurological weakness, paralysis, reduce muscle tone (even breathing one)
• Reduce wrinkle
• Unsuccessfully used as bioterror agent

Question 36

5 Types of botulism

Answer 36

• Foodborne
• Wound
• Infant
• Adult intestinal toxemia: rare
• Iatrogenic: too much botulinum toxin in cosmetic

Question 37

Cholera

Answer 37

• Non-toxigenic: in water

- Toxin-producing: infected with ctx gene bacteriophage

Question 38

Mechanism of cholera

Answer 38

1. Catalytic portion find G-proteins of cellular signaling and attach ADP molecule to them
2. G-protein convert into permanently active state to send never-ending signal
3. The cell confuses and transports a lot of water and sodium to outside
4. Intestine is flood

Question 39

What CFTR do?

Answer 39

Movement of chloride ions in and out of cell