Host /Pathogen Interactions

Question 1

Microbiota

Answer 1

aka flora; the microorgs that normally colonize various sites on/within the body w/o causing disease (Resident and transient)

Question 2

Resident Microbiota

Answer 2

inhabit sites for extended periods of time

Question 3

Transitent

Answer 3

temporarily inhabit

Question 4

colonization

Answer 4

ability of a microbe to stay affixed to a body surface and replicate (factors include adhesins, environmental, and susceptibility to pathogens)

Question 5

Where do microbiota colonize?

Answer 5

everywhere except the blood, CSF, and internal organs (these are sterile unless infected)

Question 6

blood sample with bacteria

Answer 6

infected

Question 7

Functions of microbiota

Answer 7

1st line of defense (cover binding sites, consume nutrients, produce toxins) and Aid in digestion, vitamin production, and drug metabolism (also still learning more due to human microbiome project)

Question 8

Where do we get our microbiota

Answer 8

mainly our mothers-oral, cutaneous, vaginal, mammary (all can be blocked by modern practices i.e. c-section, bottle feeding etc.)

Question 9

When is a babies microbiome similar to an adults?

Answer 9

by age 3

Question 10

Opportunistic Condtions

Answer 10

normal microbiota composition change, displacement of normal microbiota, weekend immune system (from immune suppression, AIIDS, or age/stress)

Question 11

Endogenous

Answer 11

opportunistic pathogen that is common in microbiota

Question 12

exogenous

Answer 12

opportunistic pathogen that is common in the environment

Question 13

True Pathogens

Answer 13

Infect even healthy hosts with healthy immune systems; they can breach the defenses, and are NEVER part of the normal immune system

Question 14

infection

Answer 14

successful colonization (multiplication) with or without invasion of microorganisms within a host with or without disease

Question 15

Extracellular

Answer 15

pathogens, replicate outside of cells in the host

Question 16

intracellular

Answer 16

obligate or facultative; pathogen, replicates inside the host cells in the host

Question 17

asymptomatic or subclinical

Answer 17

infection w/o disease

Question 18

symptomatic

Answer 18

infection w/ disease; next is recovery or disease then death

Question 19

pathogenecity

Answer 19

the ability to cause disease

Question 20

virulence

Answer 20

the quantitative ability of a pathogen to cause disease

Question 21

highly virulent

Answer 21

severe diseases

Question 22

virulence facctors

Answer 22

prts/other molecules –> ability to INFECT or cause DAMAGE to host

Question 23

Measuring virulence

Answer 23

LD50

Question 24

LD50

Answer 24

lethal dose 50; number of microbes that kills 50% of an experimental group of hosts-lower is more lethal/virulent

Question 25

low LD50

Answer 25

more virulent

Question 26

Infectious Dose (ID)

Answer 26

the minimum number of microbes required to be taken into the body to cause infection-lower is higher ID

Question 27

ID50

Answer 27

of microbes that cause infections in 50% of experimental group

Question 28

Establishment of an infection

Answer 28

1. Invade
2. Evade first defenses
3. adhere to host cell
4. replicate

Question 29

Extra steps needed for establishment of an infectious disease

Answer 29

1. Invade
2. Evade first defenses
3. adhere to host cell
4. replicate

++ Damage via toxins or immune and then resolution or progression (death)

Question 30

How pathogens evade host immune response

Answer 30

1. Spread from cell-cell w/o leaving the cell
2. frequently change structure of antigens
3. mimic host molecules on surface
4. replicate w/in host cel

Question 31

Antiphagocytic Mechanisms

Answer 31

1. Capsule –> cannot find or bind
2. inhibit lysosomal fusion
3. use virulence factors to escape phagolysosome and grow in the cytoplasm
4. resist lysosomal action and rep in cell
5. block activation of IFN-gamma so macrophage cannot activate

Question 32

use to destroy antibodies or complement

Answer 32

proteases

Question 33

Antigenic variation

Answer 33

alter structure of surface antigens, staying ahead of antibody production

Question 34

Superantigens

Answer 34

cause excessive stimulation of immune cells in a non-productive way (activate a ton of nonspecific-random-T cells)

Question 35

activate excess non-specific T cells

Answer 35

Superantigens

Question 36

Adhesin

Answer 36

general term for any microbial factor that promotes attachment

Question 37

Types of Adhesins

Answer 37

tips of fimbrae, glycocalyx, cell wall, biofilms