L12_Mechanisms of Bacterial Pathogenesis

Question 1

An infection in which the host defenses clear the pathogen before any symptoms of disease are noted is called what?

Answer 1

Asymptomatic, inapparent, subclinical infection

Question 2

A type of infection that can be passed from host to host

Answer 2

Comunnicable

Question 3

A highly communicable diease

Answer 3

Contagious

Question 4

An infection that comes from the environment, not a previous host (botulism, Legionnaires)

Answer 4

Noncommunicable

Question 5

An infection in which the disease subsides, but microorganisms remain in the body and can restart disease later on is called what?

Answer 5

Latent Infection

Question 6

Host survives disease but continues to shed the pathogen indefinitely

Answer 6

Chronic carrie state

Question 7

Describe the likelihood to cause disease, virulence, LD50, and ID 50 of a nonpathogen

Answer 7

Very unlikely to cause disease, very low virulence, very high LD50, very high ID50

Question 8

Describe the likelihood to cause disease, virulence, LD50, and ID 50 of an Opportunistic Pathogen

Answer 8

unlikely to cause disease unless host is debilitated, low virulence, High LD50, Low ID50

Question 9

Describe the likelihood to cause disease, virulence, LD50, and ID 50 of a pathogen

Answer 9

routinely causes disease in previously healthy host, mid to high virulence, low-mid LD50, range of ID50

Question 10

What is a Virulence factor?

Answer 10

A gene found experimentally necessary for pathogens to produce disease.

Question 11

Name some of the various functions of virulence factors (Top 5 categories)

Answer 11

survive extreme environments, adhesion, immune evasion, host cell takeover, poisoning the host.

Question 12

One major category of virulence factors is exotoxins, secreted from the pathogen or injected into the host cell by T3SS, profound toxicity of these particles may result from the following effects

Answer 12

superantigenicity, interference with signal transduction, depolymerization of actin, or other activities.

Question 13

What are toxoids and how are they made?

Answer 13

Heat or chemically inactivated exotoxins used for vaccines

Question 14

Where are exotoxins generally coded?

Answer 14

Accessory DNA that comes into cell on plasmids or by phage injection, several factors may be regulated together on pathogenicity islands.

Question 15

What are endotoxins and how do they work? Is vaccination protective agains them?

Answer 15

They are intrinsic toxins on the surface of bacterial. They cause immunogenic symtoms, neither previous exposure nor vaccination is protective.

Question 16

What is a siderophore?

Answer 16

A molecule that binds and transports iron in microorganisms

Question 17

Name three routes of vertical transmission of pathogens from a previous human host

Answer 17

Transplacental, Vaginal Delivery, Breast Milk

Question 18

What is it called when a pathogen is transmitted from an animal to a human?

Answer 18

Zoonosis

Question 19

What is a fomite?

Answer 19

any object or substance capable of carrying infectious organisms, such as germs or parasites, and hence transferring them from one individual to another. (washcloth, countertop, etc.)

Question 20

What is a vector?

Answer 20

vectors are organisms that transmit infections from one host to another

Question 21

Give two examples of how pathogens can attach to host surfaces

Answer 21

Pili/fimbrae and biofilms

Question 22

Describe the pyogenic and Ganulomatous immune responses and the main cell type involved in each.

Answer 22

Pyogenic- pus-forming, predominantly neutrophils

Granulomatous: macrophage kills most of bacteria, but some survive inside macrophages within a ganuloma.

Question 23

endotoxins induce an immunogenic response which usually results in the overproduction o what two chemicals

Answer 23

TNF and IL-1

Question 24

Name two species well know for producing superantigens

Answer 24

Strep pyogenes and Staph Aureus

Question 25

Describe the 4 typical stages of infection.

Answer 25

Incubation, prodrome (nonspecific immunogenic symptoms like fever and fatigue), Specific Illness (Pathogen mediated symptoms), Recovery/convalescence

Question 26

List four examples of virulence factors that help to survive extreme environments.

Answer 26

pH tolerance, Siderophores, Resistance to drying, resistance to detergents

Question 27

Lis three examples of virulence factors that help in Host Cell takeover

Answer 27

Endosome escape pathway, actin polymerization, type 3 and 4 secretion systems

Question 28

List three virulence factors that help with Adhesion

Answer 28

pili/fibrae, slime layer, adhesins

Question 29

List five virulence factors that assist with immune evasion

Answer 29

Capsule (resists phagocytosis), IgA protease, Macrophage apoptosis factors, Antigenic Variation (trioanosomes), Serum resistance (ability to withstand complement)

Question 30

List three virulence factors that assist in poisoning the host

Answer 30

Tissue degrading enzymes (usually exotoxins), Endotoxins, and Exotoxins

Question 31

List two virulences factors that avoid phagocytosis

Answer 31

Capsule and M Protein

Question 32

What are the two obligate intracellular organisms?

Answer 32

Chlamydia and Rickettsia

Question 33

Can you produce vaccines against exotoxins?

Answer 33

Yes

Question 34

Which organism when overgrown causes pseudomembranous colitis?

Answer 34

C. Difficile