Mechanisms of Bacterial Pathogenesis

Question 1

Examples of disease states where host clears the pathogen before symptoms of disease are noted

Answer 1

asymptomatic, inapparent, subclinical

Question 2

What is a communicable infection?

Answer 2

An infection that can be passed from host to host

Question 3

Where do noncommunicable infections come from?

Answer 3

the environment

Question 4

Describe the action of a latent infection

Answer 4

an infection in which the disease subsides but microorganisms remain in the body and can restart disease later

Question 5

What is a chronic carrier?

Answer 5

a host in which the disease continues without symptoms and the host continues to shet the pathogen indefinitely

Question 6

Are pathogens, parasites?

Answer 6

Yes, they harm the host by taking its resources

Question 7

What are all viruses?

Answer 7

Obligate intracellular parasites

Question 8

Most bacteria are?

Answer 8

facultative intracellular parasites

Question 9

What is the virulence, LD50, and ID50 of nonpathogens?

Answer 9

Low virulence and extremely high LD and ID50

Question 10

What is the virulence, LD50, and ID50 of opportunistic pathogens?

Answer 10

Low virulence, High LD50 and slightly lower ID50

Question 11

Who do opportunistic pathogens most commonly infect?

Answer 11

immunosuppressed/ injured hosts

Question 12

Give examples of Opportunistic Pathogens

Answer 12

Psuedomonas, eterobacter, klebsiella

Question 13

What is the virulence, LD50, and ID50 of highly pathogenic ?

Answer 13

High virulence and mid to low LD50

Question 14

What is virulence a measure of?

Answer 14

numerical measure of pathogenicity. it is measured by ID50 and LD50

Question 15

What enhances pathogenicity?

Answer 15

virulence factors

Question 16

What are the main functions of virulence?

Answer 16

1- Survival in extreme environments
2- Adhesion to host surfaces
3- Immune evasion
4- Take over host cells
5- Poison the host
6- Endotoxins

Question 17

What types of environments can pathogens adapt themselves to in order to increase virulence?

Answer 17

pH extremes, resistance to drying and detergents, and low iron environments

Question 18

What are some adhesion mechanism of pathogens?

Answer 18

Pili, slime layer

Question 19

What helps pathogens resist phagocytosis?

Answer 19

Capsules (gram - mostly)

Question 20

Name some immune system evasion tactics

Answer 20

Induce apoptosis of macrophages, IgA proteases, antigenic variation

Question 21

How do pathogens take over host cells?

Answer 21

T3SS and T4SS, endosome escape routes, and actin polymerization pathway for cell to cell spread

Question 22

What are exotoxins?

Answer 22

secreted polypeptides that are encoded on accesory DNA that come in on plasmids or by phage infectin

Question 23

How are exotoxins released?

Answer 23

secreted from the cell or injected by T3SS

Question 24

Structure of exotoxins?

Answer 24

A-B subunit system. A is toxic and B helps bind to the cell

Question 25

What are the functions of exotoxins?

Answer 25

1- interfere wtih signal transduction
2- cause depolymerization of actin
3- act as supertoxins

Question 26

What is a good vaccine item?

Answer 26

Heat or chemically inactivated exotoxin. The toxin becomes a toxoid.

Question 27

What are endotoxins?

Answer 27

intrinsic to the surface of bacteria and cause immunogenic symptoms

Question 28

What are examples of endotoxins?

Answer 28

Gram (-) LPS, Gram (-) LOS, and Gram (+) teichoic acids

Question 29

What is the timeline of infectious disease?

Answer 29

1- incubation period
2- prodromal period
3- specific-illness period
4- recovery convalescence

Question 30

Stages of bacterial pathogenesis.

Answer 30

1- Transmission of pathogens
2- attachment of pathogens to host surfaces
3- Invasion, inflammation, intracellular survival
4- survival inside host cells
5- poisoning the host (exotoxins)

Question 31

What is the pyogenic inflammatory immune response?

Answer 31

pus forming, predominantly neutrophils

Question 32

What is the granulomatous inflammatory response?

Answer 32

macrophages kill most of the bacteria but some can survive inside macrophages within a granuloma