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Microbio > Unit 4: Chapter 34 > Flashcards

Unit 4: Chapter 34 Flashcards

1
Q

Host

A

larger organism that supports survival and growth of pathogenic microorganism

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2
Q

Infection

A

microbe growing and multiplying on or within a host
may or may not result in overt disease

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3
Q

Infectious disease

A

any change from a state of health
part or all of host incapable of carrying on normal function due to presence of pathogen or its product

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4
Q

Infection vs colonization

A

Infection: conditions from colonization of host that can cause disease
Colonization: denotes physical presence of microorganisms

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5
Q

___ can cause infections when opportunity given

A

colonization

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6
Q

Pathogen

A

any organism that cause disease

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7
Q

Opportunistic pathogen

A

may be part of normal microbiota and cause disease when host is immunocomprised

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8
Q

Pseduomas aeuroginosa

A

Not part of normal flora
Opportunistic pathogen

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9
Q

Extracellular pathogens

A

remain in tissues and fluids but never enter host cells during disease

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9
Q

Virulence

A

degree of harm (pathogenicity) inflicted on its host

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10
Q

Pathogenicity

A

ability of pathogen to cause disease

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11
Q

A pathogen must contact ______ and survive within it to cause _____

A

a host, disease

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12
Q

Intracellular pathogens

A

Grow and multiply within host cells

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13
Q

Faculative intracellular pathogens

A

reside within cells of host and can also grow without host cell support in pure culture

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14
Q

Obligate intracellular pathogens

A

reside within cells of host and needs host to reproduce and survive

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15
Q

Factors affecting success of transmission

A
  1. Virulence of organism
  2. Number of invading organisms
  3. Presence of adhesion and invasion factors
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16
Q

The best defensive system against pathogens is:

A

immune system based on healthy diet and exercise

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17
Q

Invading organism competes ____ for resources and survive host ______ ________

A

resident microbiota (normal flora) ; defense mechanism

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18
Q

Disease ensues when organism produces molecules that
directly damage ______ or stimulates ______

A

host cells
host immune cells to destroy infected tissue

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19
Q

Tranmission

A

entry into the host

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20
Q

Animate transmission

A

Living
(animals, humans)

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21
Q

Inanimate transmission

A

Nonliving
(water, food)

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22
Q

Reservoir

A

natural environment location in which pathogen normally resides

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23
Q

Vector

A

Organism that spreads disease from one to another

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24
Mosquitoes, ticks, fleases, mites, biting flies are examples of
vector
25
Pathogen transmission occurs either _____ or ______
directly, indirectly
26
4 main routes of pathogen transmission:
1. Airborne 2. Contact 3. Vehicle 4. Vector borne
27
Vertical transmission
Pregnant women pass pathogen to their unborn child (infected mother to child)
28
Examples of Direct transmission
horizontal contact (kissing) airborne droplets vector vertical contact (mother to child)
29
Examples Indirect transmission (vehicles)
Contact (fomites) Food Water Biological products Airborne (droplet nuclei and aerosolized droplets like dust)
30
Fomites
inanimate objects that can carry disease Ex. Table, microphones, door handles
31
Horizontal transmission
Transmission of infection from person to person
32
Horizontal Transmission through _____
7 F'S 1. Flies 2. Fluids 3. Food 4. Feces 5. Fingers 6. Fomites 7. Fornication
33
The efficiency of transmission increases with
extensive multiplication
34
Pathogens virulence may be influenced by its ability to
live outside its host
35
True or False: Exposure is enough to make infection to occur
False: infection is not enough to make infection!
36
Tropism
Pathogen must make contact with appropriate host tissue by cell surface receptors
36
Infection occurs by ___ and _____
exposure and tropism
37
Droplets
direct airborne transmission produced when liquids are placed under force (saliva, mucus) can travel up to 1 meter (why social distance exists) up to 2 mm in diamter
38
Most human diseases are transmitted by the ___ system through any other system
Respiratory
39
Droplet nuclei
indirect airborne transmission result from evaporation of larger droplets may remain airborne for hours or days and travel long distances 1 to 5 um diamter
40
Dust particles
indirect airborne transmission can survive long periods outside host
41
Droplet nuclei can reach
the lung
42
Tuberculosis (TB)
Caused by mycobacterium Example of droplet nuclei Patient cough into air release droplet nuclei which float into air and can last several hours to be inhaled by a person
43
Aerosolized dust particles
smaller than 1 um and can be dispersed way further
44
Contact transmission
host touching source or reservoir of the pathogen
44
Direct contact is
person to person physical interaction is required
44
Indirect contact
involves inanimate objects (fomite) that transfers infectious agent between hosts
45
Vehicles
materials that indirectly transmit pathogens
46
Examples of vehicles
Surginal instruments Drinking vessels Food Water Biological materials (fluids and tissues) Air
47
Vector
living organism that transmits a pathogen highly virulent
48
Vector organisms include ___ and ___
mostly anthropods: insects, ticks, mites, flies vertebrates: dogs, cats, skunks, bats
49
In vector borne transmission, pathogen benefit because ___ and ____
extensive reproduction spread between hosts
50
Vector born diseases include
Malaria, typhus, and sleeping sickness
51
In vector borne transmission, pathogens do not harm what nd why?
their vector because host and pathogen vector are closely related as reproduction connect the two
52
What is more common? Vertical or horizontal transmission
horizontal transmission
53
Babies born with infectious disease from vertical transmission are said to have:
congenital infection Ex. gonorrhea, symphillus, german measles, toxoplasmois, listeria, zika virus
54
Infectious Dose (ID50)
Number of microbes required to cause disease in 50% of inoculated hosts
55
Highly virulent pathogenns have ___ value of ID50 and LD50 than does moderately virulent one
lower
56
More virulent strain is identified as
Low ID50 and LD50 lower number of organisms needed to infect 50% of hosts
57
Vibrio cholerae
large infective dose (10^7) since it is easily destroyed by stomach acid (higher number of organisms cause disease)
58
Shigella
requires very small infective dose (small number of organisms cause disease)
59
Lethal Dose (LD50)
dose that kills 50% of a group of experiemntal hosts within a specified period
60
Lethal dose is influenced by
susceptibility of host by imune system, nutrition, cleanliness, and emotional health
61
__ and _____ establish colonization
entry, adhesion
62
Portal of entry for pathogens
1. skin 2. respiratory 3. gastrointestinal 4. urogenital system 5. conjuctive of eye
62
Adhesion
cell-surface components that help bacteria attach to target cells
63
Adhesions have high degree of ___ to _____
specificity, target tissues
64
Microbial adherence structures:
1. Pilli 2. Fimbriae 3. Membrane and capsular materials 4. Specialized adhesion molecules on microbe's cell surface
65
Bacteremia
presence of viable bacteria in the blood
65
Invasion
once under mucous membrane, a pathogen can penetrate deep issues
66
Septicemia
bacterial or fungal toxins in the blood
67
Clostridium tetani (Tetanus)
Noninvasive Does not spread from oen tissue to another but toxins become blood borne
68
Bacillus anthracis (anthrax) and Yerinia pestis (Plague)
Highly invasive Produces toxins
69
Invasion of intracellular bacterial pathogens use ______
actin filament tail
70
Actinn tail propels bacteria by
host cell surface where it forms protrusion and helps with invasion
71
Profusion from actin tail is engulfed by
adjacent cell and evades immune response
72
Pathogenicity Islands
Large segments of bacterial chromosomes and plasmid DNA to encode for virulence factors
73
Toxin
substance that disrupts normal metabolism of host cells
73
Toxigenicity
Pathogen's ability to produce toxins
73
Intoxications
Diseases that result from entry of a specific performed toxin into host Ex. S. aureus
73
What helps the pathogen survive host defenses?
Pathogenicity Islands
74
3 ways pathogenicity islands help survive host defenses
1. increase bacterial virulence 2. absent in nonpathogenic membranes of same genes and species 3. genes can spread from one bacterial cell to another
75
Intoxications don't require presence of ___ but require presence of ___
pathogen, toxin
76
Intoxication vs. infection
Intoxication: disease from entry of toxin and organism does not have to enter body Infection: organism needs to enter body and go to target to attach to receptor
77
Exotoxins
AB toxin (2 subunit protein) gram + and gram - heat susceptible (not resistant) more toxic
78
Endotoxins
Lipid A Onlyn gram - Heat stable and resistant less toxic
79
__ are among most lethal substances known
exotoxins
80
How can exotoxins be transferred?
From organism to organism by genes on plasmids or prophages
81
AB toxin
In exotoxin and protein 2 subunits 1. A subunit: catalyze reaction that cause toxicity 2. B subunit: binds to host cell receptor
82
Superantigens
Endotoxin Stimulate about 30% of host T cells of immune cells which encode for cytokines and release proinflamatory molecules
83
Cytokines by T cells of superantigens result in
failure of multiple host organs
84
Endotoxin lipid polysaccharide located in
gram negative cell wall and is toxic to mammals
85
Why are endotoxins called endotoxins
Bound to bacterium and released when microorganism lyses
86
What causes fever?
endotoxin
86
The toxic componet in lipid portion of endotoxins is
Lipid A

Microbio (18 decks)

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