Pathogenicity

Question 1

What can toxins cause?

Answer 1

Food poisoning
Cancer
Perio
Inappropriate immune response

Question 2

What is the main type of endotoxin?

Answer 2

LPS
Lipopolysaccharide

Question 3

What are the types of exotoxin?

Answer 3

Pore forming
Surface acting
Intracellular

Question 4

What are endotoxins produced by?

Answer 4

Gram negative bacteria

Question 5

What are the main features of endotoxins?

Answer 5

Heat stable
Poorly antigenic
Cause cytokine storm and inflammation
Cause of shock and fever

Question 6

How do they interact with body cells?

Answer 6

Lipid A of endotoxin binds to CD14 and TLR4
Produces cytokines

Question 7

How do toxins damage the membrane?

Answer 7

Enzymes
Pore formation

Question 8

Which toxins are membrane acting?

Answer 8

Small toxins
Proteases
Super antigens

Question 9

What is a small toxin and how does it work?

Answer 9

Small cysteine rich protein
Produced by enterotoxics
Molecular mimicry

Question 10

What do super antigens result in?

Answer 10

Toxic shock syndrome
Excessive activation of T cell immune response

Question 11

What are the steps in intracellular toxin attack?

Answer 11

Cell binding
Membrane translocation
Enzymatic action

Question 12

What are the most well known neurotoxins?

Answer 12

Botulinum
Tetanus

Question 13

How do neurotoxins work?

Answer 13

Attack signalling across synapses
Block transmitters

Question 14

What are symptoms of diphtheria?

Answer 14

Inflamed throat
Diphtheritic membrane in throat
Fever

Question 15

What causes death from diphtheria?

Answer 15

Strangulation
Toxicity

Question 16

How does diphtheria cause disease?

Answer 16

Inhibiting protein synthesis

Question 17

What non-toxin diseases use type III and IV secretion systems?

Answer 17

Versiona pestis: plague, salmonella
Typhoid
Shigellosis

Question 18

What did type III secretion system evolve from?

Answer 18

Flagellum

Question 19

What did type IV secretion system evolve from?

Answer 19

Pilli

Question 20

What is pathogenicity?

Answer 20

Ability to cause disease

Question 21

What is virulence?

Answer 21

Degree of pathogenicity

Question 22

What is a virulent bacteria?

Answer 22

Usually cause disease when they infect

Question 23

What is a virulent factor?

Answer 23

Bacteria/component only involved in pathogenesis

Question 24

What is a housekeeping gene?

Answer 24

Gee involved in all aspects of bacteria’s life

Question 25

What are koch’s postulates?

Answer 25

Pathogen occurs in every case of disease Pathogen does not occur in healthy subject After isolation, pathogen can induce disease in healthy subject

Question 26

What are molecular koch’s postulates?

Answer 26

Phenotype associated more often Inactivation of virulent genes decrease disease Restoration of full pathogenicity happens when mutated gene is replaced with wild type

Question 27

What are virulence genes often encoded on?

Answer 27

Plasmids Transposons Bacteriophages

Question 28

How do microbes adhere to surfaces?

Answer 28

Flagellae Pilli Surface proteins

Question 29

What is colonisation?

Answer 29

Presence of microbes without accompanying disease

Question 30

Define infection

Answer 30

Presence of microbes that results in disease

Question 31

What must microbes be able to do in order to survive in their host?

Answer 31

Have effects on host Evade immune defenses Inactive immune cells

Question 32

What properties of microbes aid invasion?

Answer 32

Enzymes Antiphagocytic capsule and M proteins Toxins

Question 33

How can intracellular microbes invade a cell and how do they survive?

Answer 33

Taken into cell by phagocytosis or endocytosis Modify phagosome compartments Nullify host response

Question 34

What are 3 examples of obligate intracellular bacterial pathogens?

Answer 34

Myobacterium leprae Chlamydiaceae Typhyus

Question 35

Where does typhus replicate?

Answer 35

In the cytoplasm

Question 36

What are some general features of obligate intracellular bacteria?

Answer 36

Long generation time Exogenous energy supply Can infect non-phagocyte cells

Question 37

What are the advantages of a microbe being intracellular?

Answer 37

Immune evasion Carried around body Obtain nutrients from host

Question 38

When does the immune system cause disease?

Answer 38

Pyogenic inflammation - acute Can get shock from cytokine storm and organ failure Granulomatous inflammation - chronic Granulomas form

Question 39

What is a cytokine storm?

Answer 39

Over activation of healthy immune system Cause tissue damage, organ failure, shock, death Causes sepsis

Question 40

What are damages cause by immune response?

Answer 40

Mimicry Cytokine induction Toxins