L12_Mechanisms of Bacterial Pathogenesis Flashcards Preview

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Flashcards in L12_Mechanisms of Bacterial Pathogenesis Deck (34):
1

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

Asymptomatic, inapparent, subclinical infection

2

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

Comunnicable

3

A highly communicable diease

Contagious

4

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

Noncommunicable

5

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

Latent Infection

6

Host survives disease but continues to shed the pathogen indefinitely

Chronic carrie state

7

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

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

8

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

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

9

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

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

10

What is a Virulence factor?

A gene found experimentally necessary for pathogens to produce disease.

11

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

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

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

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

13

What are toxoids and how are they made?

Heat or chemically inactivated exotoxins used for vaccines

14

Where are exotoxins generally coded?

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

15

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

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

16

What is a siderophore?

A molecule that binds and transports iron in microorganisms

17

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

Transplacental, Vaginal Delivery, Breast Milk

18

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

Zoonosis

19

What is a fomite?

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.)

20

What is a vector?

vectors are organisms that transmit infections from one host to another

21

Give two examples of how pathogens can attach to host surfaces

Pili/fimbrae and biofilms

22

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

Pyogenic- pus-forming, predominantly neutrophils
Granulomatous: macrophage kills most of bacteria, but some survive inside macrophages within a ganuloma.

23

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

TNF and IL-1

24

Name two species well know for producing superantigens

Strep pyogenes and Staph Aureus

25

Describe the 4 typical stages of infection.

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

26

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

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

27

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

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

28

List three virulence factors that help with Adhesion

pili/fibrae, slime layer, adhesins

29

List five virulence factors that assist with immune evasion

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

30

List three virulence factors that assist in poisoning the host

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

31

List two virulences factors that avoid phagocytosis

Capsule and M Protein

32

What are the two obligate intracellular organisms?

Chlamydia and Rickettsia

33

Can you produce vaccines against exotoxins?

Yes

34

Which organism when overgrown causes pseudomembranous colitis?

C. Difficile