Host pathogens

Question 1

microbiota

Answer 1

the microorganisms that normally colonize various sites in/within the body without causing disease

Question 2

resident microbiota

Answer 2

inhabit sites for extended periods

Question 3

transient microbiota

Answer 3

inhibit temporarily for days, weeks, or months then disappear

Question 4

colonization

Answer 4

ability of microbe to stay affixed to a body surface and replicate

Question 5

what does our microbiota do

Answer 5

competitively exclude pathogens
- covering of binding sites prevents attachment
- consumption of available nutrients
- production of compounds toxic to other bacteria

Question 6

how is microbiota acquired

Answer 6

humans are initially colonized by microorganisms at birth

Question 7

what can perturb our microbiota

Answer 7

by age 3, a child’s microbiome looks a lot like an adult’s and it becomes much more stable

Question 8

pathogen

Answer 8

any bacterium, virus, fungus, protozoan, or helminth that causes disease

Question 9

pathogenicity

Answer 9

the ability of an organism to cause disease

Question 10

true (primary) pathogens

Answer 10

can cause disease in a host regardless of the host’s resident microbiota or immune system
* are never part of the normal microbiota

Question 11

opportunistic pathogens

Answer 11

cause disease only under opportunistic conditions
- changes in the composition of the normal microbiota
- can be members of normal microbiota or common in the environment

Question 12

infection

Answer 12

successful colonization and multiplication of microorganism within a host with or without the manifestation of disease

Question 13

infectious disease

Answer 13

illness caused by damage to host cells by an infectious agent or its products resulting in signs and symptoms

Question 14

virulence

Answer 14

degree or severity of disease

Question 15

lethal dose 50 (LD50)

Answer 15

the number of microbes that kills 50% of an experimental group of animal hosts

Question 16

infectious dose 50 (ID50)

Answer 16

number of microbes that will cause infection in approximately 50% of an experimental group of hosts

Question 17

stages of pathogenesis

Answer 17

exposure and entry
adhesion to skin or mucosa
invasion through epithelium and immune invasion
infection
toxins or host immune response
tissue damage, disease

Question 18

fecal-oral portal of entry

Answer 18

through mucosal surfaces of gastrointestinal transportct

Question 19

respiratory portal of entry

Answer 19

through musical surfaces of respiratory tract

Question 20

transplacental portal of entry

Answer 20

through the placenta to infect a fetus

Question 21

skin portal of entry

Answer 21

through epithelial surfaces

Question 22

urogenital portal of entry

Answer 22

through mucosal surfaces of genital and urinary tracts

Question 23

parenteral portal of entry

Answer 23

through injection into the bloodstream (for example, infect bites or needle sticks)

Question 24

adhesion

Answer 24

fimbriae adhesions
cell wall adhesions
glycocalyzx (slime and capsular polysaccharides)

Question 25

invasion

Answer 25

ability of some pathogens to spread through tissues produce enzymes or toxins which serve as virulence factors that allow them to colonize and damage host tissues as they spread deeper into body

Question 26

immune evasion : antigenic variation

Answer 26

acquire changes in the genes for surface antigens that alter the structure of surface antigens that antibodies would otherwise recognize

Question 27

virulence factors for immune evasion

Answer 27

capsule protease

Question 28

some bacteria resist phagocytic destruction by

Answer 28

preventing fusion of the lysosome with the phagosome escaping from the phagosome before the lysosome fuses preventing acidification of the phagosome resisting killing by lysosomal chemicals

Question 29

exotoxins

Answer 29

proteins produced by pathogenic bacteria (gram positive and negative) and secreted

Question 30

endotoxins

Answer 30

lipid A portions of LPS that are part of the outer membrane of the cell wall of gram negative bacteria. they are liberated when the bacteria die and the cell wall breaks apart

Question 31

exotoxin mode of action: cytolytic toxins

Answer 31

work by disrupting the cytoplasmic membrane integrity, causing cell lysis and death

Question 32

exotoxin mode of action: AB toxins

Answer 32

consist of two subunits, A and B. B subunit binds host cell receptor and transfers subunit A across the cell membrane and this usually inhibits protein synthesis or disrupts ion homeostasis

Question 33

exotoxin mode of action : superantigen toxins

Answer 33

overactivate the immune system by activating non specifically CD4+ T cells which leads to an excessive cytokine release and excessive inflammatory response

Question 34

most genes for exotoxins are carried on

Answer 34

plasmids or phages

Question 35

body makes antibodies (anitoxins)

Answer 35

provide immunity

Question 36

inactivate exotoxin (heat, chemical)

Answer 36

toxoid vaccine to stimulate antibody production

Question 37

in an endotoxin ____ is the toxic part

Answer 37

lipid A

Question 38

endotoxins only come from gram _

Answer 38

negatie

Question 39

high/low dose of exotoxin

Answer 39

low

Question 40

high/low dose of endotoxin

Answer 40

high

Question 41

are exotoxins release actively or passively from bacteria

Answer 41

actively

Question 42

are endotoxins released actively or passively from bacteria

Answer 42

passively

Question 43

endemic

Answer 43

disease consistently present (often as low level) in a population

Question 44

sporadic

Answer 44

when occasional cases are reported as irregular intervals

Question 45

epidemic

Answer 45

occurrence of more cases of disease then expected in a given area over a particular period of time

Question 46

pandemic

Answer 46

an epidemic occurring on several continents and usually affecting an exceptionally high proportion of the global population

Question 47

prevalence

Answer 47

number of existing cases of disease in a population during a defined period of time - how much of a population is affected

Question 48

incidence

Answer 48

number of new cases of disease that vela in a population during a defined period of time - how quickly are people becoming infected

Question 49

mortality rate

Answer 49

incidence of death due to a disease during a particular time period

Question 50

case fatality rate

Answer 50

mortality rate / incidence rate

Question 51

infectious disease

Answer 51

may or may not be communicable

Question 52

communicable disease

Answer 52

an infectious disease that is contagious and which can be transmitted from one infected host to another

Question 53

period of disease

Answer 53

incubation period prodromal period period of illness period of decline period of convalescence

Question 54

droplet transmission

Answer 54

close range (within 3 feet)

Question 55

fomites

Answer 55

inanimate objects that transmit pathogens

Question 56

droplet nuclei

Answer 56

inhaled by those over a long distance

Question 57

zoonoses

Answer 57

when a disease comes from animals

Question 58

acute disease

Answer 58

symptoms develop rapidly

Question 59

chronic disease

Answer 59

symptoms develop gradually over months or years of lifetime and are slow to resolve

Question 60

latent disease

Answer 60

the causal pathogen goes dormant for extended periods of time with no active replication. no symptoms unless organism reactivates and infection again becomes acute