Basic Principles of Infectious Disease (Bacterial Pathogenesis)

Question 1

normal flora

Answer 1

microbes on the body of healthy individuals

Question 2

Do all individuals have the same normal flora?

Answer 2

no, they are individuals

Question 3

Factors which Affect Normal Flora

Answer 3

host, diet, health, etc.

Question 4

frank pathogen

Answer 4

capable of causing disease regardless of the status of the host immune system (both healthy and immunocompromised)

Question 5

obligate pathogen

Answer 5

pathogen that cannot survive [very long] outside of the host

Question 6

opportunistic pathogen

Answer 6

disease which occurs under favorable conditions for the pathogen (ex: microbial overgrowth, trauma, decreased immune status/function, antibiotic tx, etc)

Question 7

What type of pathogen will we encounter most - frank, obligate, or opportunistic?

Answer 7

opportunistic

Question 8

commensals

Answer 8

another name for normal flora

Question 9

Synthesized Products of Microbes to kill other microbes (4)

Answer 9

1. Naturally derived antibiotics
2. Secondary metabolites
3. Bacteriocins (antimicrobial peptides from bacteria)
4. T6SS Effectors

Question 10

Type 6 Secretion System Effectors

Answer 10

secrete a very specialized bacterial toxin

Question 11

Most adapted microbes?

Answer 11

normal flora (to live in “harmony” with the host

Question 12

Most maladapted microbes?

Answer 12

those that cause acute [rapidly fatal] disease because if you have a dead host then you don’t have a place to live and then you die too

Question 13

[Additional] Possible Synthesized Products of Normal Flora

Answer 13

Vitamins B12 and K

Question 14

Disease

Answer 14

disturbance of proper function

Question 15

By what factor must bacteria outweigh host cells to cause disease?

Answer 15

10

Question 16

Is it disease from the host or microbe perspective?

Answer 16

host!

it is incidental (accidental) to the microbe

Question 17

pathogenic

Answer 17

ability to cause disease (qualitative)
used synonymously with virulent

Question 18

virulent

Answer 18

ability to cause disease (qualitative)
used synonymously with pathogenic

Question 19

virulence

Answer 19

disease-producing potential (quantitative measurement)

Question 20

infection

Answer 20

establishing a host-parasite/host-microbe relationship

Question 21

etiology

Answer 21

cause of disease

Question 22

Can a disease have multiple etiologies?

Answer 22

of course!
(superinfections, polymicrobials, etc)

Question 23

Can just any ol microbe cause disease?

Answer 23

YES (because it is highly dependent on host status)

Question 24

adaptive radiation definition

Answer 24

an evolutionary process that produces new species from a single, rapidly diversifying lineage

Question 25

adaptive radiation in the context of chronic infection

Answer 25

microbes can mutate and have change in their disease causing potential; done as a way to evade the host immune system

Question 26

Framework of Host-Microbe Interactions and Disease Progression (6-8)

Answer 26

1. Encounter 2. Entry 3. Spread 4. Multiplication 5. Damage 6. Outcome (7. Transmission) (8. Treatment and Prevention)

Question 27

reservoir

Answer 27

source of microbe

Question 28

2 Modes of Transmission

Answer 28

1. Direct (contact with reservoir) 2. Indirect (living vector or inanimate fomite or vehicle)

Question 29

nosocomial

Answer 29

hospital-acquired

Question 30

Endogenous encounter

Answer 30

opportunistic flora within the host

Question 31

Exogenous encounter

Answer 31

other patients (outside the host)

Question 32

Entry

Answer 32

how a microbe gains access into the host, past host defenses

Question 33

Possible Routes of Entry

Answer 33

Question 34

Two Types of Spread

Answer 34

1. Local 2. Systemic

Question 35

Example of Pathogen that uses Local Spread

Answer 35

Listeria monocytogenes literally shoots out an invades adjacent cells

Question 36

colonization

Answer 36

ability to be non-transient

Question 37

Example of Pathogen with Systemic Dissemination

Answer 37

Streptococcus pneumonia

Question 38

Examples of Ways Microbes Can Spread

Answer 38

bloodstream, survival in phagocytes (like a Trojan horse), bore through tissue, or obligate intracellular pathogens

Question 39

quorum sensing

Answer 39

cell–cell communication that allows bacteria to share information about cell population density and adjust gene expression accordingly

Question 40

Do microbes have to compete with one another for resources?

Answer 40

obviously

Question 41

incubation period

Answer 41

time between encounter/entry and signs of disease

Question 42

Effect of fever on microbial growth rate?

Answer 42

decrease (possibly)

Question 43

Host Tissue Tropism

Answer 43

some microbes like to spread in one tissue over another

Question 44

Two Components of Damage

Answer 44

1. Damage by microbe 2. Damage by excessive host immune responseD

Question 45

Damage by Microbe

Answer 45

exotoxins, endotoxins, growth on host tissue

Question 46

Damage by Excessive Host Immune Response

Answer 46

inflammation, autoimmunity, superantigen (cytokine storms)

Question 47

Three Outcomes

Answer 47

1. Host wins 2. Microbe wins 3. Coexistence

Question 48

dead end

Answer 48

if a microbe kills its host it has no host and it dies

Question 49

Ways for Microbe and Host to Coexist

Answer 49

1. Persistent/Chronic Infection 2. Subclinical carrier state 3. Latent infection (like Lyme, TB, etc)

Question 50

Goal of a Microbe?

Answer 50

survive and replicate

Question 51

Examples of Transmission Mechanisms

Answer 51

diarrhea, vomiting, sneezing, coughing, ability to survive on an inanimate object, sexual