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MICRO FINAL EXAM > Ch.15 Microbial Pathogenesis > Flashcards

Ch.15 Microbial Pathogenesis Flashcards

(67 cards)

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1
Q

Virulence

A

allows the pathogen to cause disease

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2
Q

Virulence genes

A

chromosomal

plasmid

phage-based

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3
Q

what are virulence factors?

A

adherence

cell invasion

immune response inhibitors

colonization

toxins

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4
Q

how does a disease develop?

A

by virulence and virulence factor

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5
Q

PATHOGEN -> HOST
The pathogen process of infection and causing disease

A
  1. Enter Host
    -adhesion number of infecting microbes
  2. penetrate /evade host defenses
    -capsule enzymes fimbriae/pili
  3. damage host
    -toxins intracellular pathogen
  4. exit host
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6
Q

Mucous Membrane portals of entry

A

respiratory tact

gastrointestinal tract

genitourinary tract

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7
Q

skin portals of entry

A

hair follicles

sweat glands

conjunctiva

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8
Q

parental route portals of entry

A

deposition of microbes directly under the skin or mucous membrane

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9
Q

A measure of virulence:
ID50

A

infectious dose needed to cause disease symptoms in 50 experiential hosts

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10
Q

A Measure of potency :
LD50 (lethal dose 50%)

A

dose of pathogen required to kill 50% of an experimental group of animal hosts

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11
Q

Example of Measure of Virulence:
Bacillus Anthracis

A

portal of entry / ID50

skin: 10-50 endospores

inhalation: 10,000-20,000 endospores

ingestion: 250,000 - 10^6 endospores

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12
Q

Example of Measure of potency:

A

toxin/ LD50
Botulinum: 0.03 ng/kg
Shiga Toxin:i250 ng/kg
Staphylococcal enterotoxin: 1350 ng/kg

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13
Q

attachment of pathogens at the portal of entry:

A

bind via adhesins/ligands on the pathogen to host cell receptors

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14
Q

EXAMPLES of attachment of pathogens at the portal of entry:

A

glycocalyx

fimbriae

M protein of Streptococcus pyogenes

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15
Q

biofilm formation:

A

microbial community contained in exopolysaccharide matrix

adhere to surface

very resistant

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16
Q

EXAMPLES of Biofilm :

A

dental plaque

catheters

IV’s

Heart valves

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17
Q

factors that allow for bacterial invasion:

A

capsule

cell wall

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18
Q

what does the capsule do?

A

impairs phagocytosis by host cells

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19
Q

what are the cell wall components?

A

cell wall mycolic acids of Mycobacterium Tuberculosis

M protein: streptococcus pneumonia
-attachment, anti-phagocytic properties, inactivate complement

Opa Protein of Neisseria Gonorrhea and others

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20
Q

extracellular enzymes:
COAGULASES

A

clot blood

isolate bacteria from the host (staphylococci)

fibrinogen—Coagulase—-> Fibrin

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21
Q

extracellular enzymes:
KINASES

A

destroy blood clots

ex: streptokinase

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22
Q

extracellular enzymes:
HYALURONIDASE

A

hydrolyzes hyaluronic acids

polysaccharide bridging cells of connective tissue-> allow the microbe to spread

ex: streptococcus

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23
Q

extracellular enzymes:
COLLAGENASE

A

digest collagen

in the connective tissue of muscle, organs, and tissue

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24
Q

extracellular enzymes:
PROTEIN A

A

STAPHYLOCOCCUS

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25
extracellular enzymes: PROTEASES
destroy host proteins IgA protease
26
antigenic variation
alteration of pathogen surface proteins posses alternate genes
27
invasins
pathogen surface proteins that rearrange actin filaments induces membrane ruffling pathogen engulfed into the cell
28
penetration into the host cell cytoskeleton:
some pathogens enter cells of the host using filaments of the cystolention
29
what is an example of a common means of entry?
actin filaments
30
pathogen damage to host cells by: host nutrients
using host nutrients pathogen acquire host iron via siderophores Iron (Fe) Chelator
31
pathogen damage to host cells by: damage in the area of infection
causing direct damage in the vicinity of infection intracellular pathogens ex: viral infection
32
pathogen damage to host cells by: production of toxins
production of toxins; transported by blood, lymph inhibit protein s ytehsis Disruption of membrane
33
pathogen damage to host cells by: induction of hypersensitive reactions
Induction of hypersensitivity reactions overproduction of cytokines
34
exotoxins are secreted to what?
to the surrounding environment
35
what is the action of exotoxins:
destroy specific host cell structures or inhibit metabolic functions can be very lethal
36
types of exotoxins:
A-B toxins Membrane-disrupting Toxins Superantigens
37
describe the components of exotoxins
water-soluble proteins (many are enzymes most are plasmid-based or inpageges (lysogenic conversion)
38
what do toxoid forms of antitoxins do?
provide immunity
39
A-B toxins consist of what?
A: an active enzyme component B: cell binding component
40
A-B Toxin: DIPHTHERIA TOXIN
Corynebacterium diphtheriae inhibits protein synthesis phage carries tox gene
41
A-B Toxin: Botulism Toxin
Clostridium botulinum neurotoxin; prevents nerve impulses to muscles; causes flaccid paralysis.
42
A-B Toxin: Tetanus Toxin
Clostridium tetani neurotoxin tetanospasmin; blocks inhibitory nerve impulses to muscles; causes spasmodic contractions.
43
A-B Toxin: Vibrio Enterotoxin
Vibrio cholerae cholera toxin; causes cellular secretion of fluids & electrolytes -> severe diarrhea & dehydration
44
membrane-disrupting toxin:
cause lysis of host cells by disrupting the plasma membrane
45
how does membrane-disrupting toxin cause lysis of host cells by disrupting the plasma membrane?
forming protein channels in the membrane or by disrupting phospholipids
46
Leukocidins
kill phagocytic white blood cells
47
hemolysins:
kill red blood cells
48
super antigens stimulate
intense immune response of T cells
49
T cells stimulated to produce:
cytokines regulate immune response
50
what happens due to excessive cytokine levels?
enter the bloodstream and induce symptoms can lead to shock & death
51
Erythrogenic toxins (Streptococcus pyogenes):
damage blood capillaries under the skin Cause: rash; scarlet fever.
52
Staphylococcal enterotoxin
superantigen (S. aureus)
53
what are endotoxins?
are the lipid portion (lipid A) of the LPS (lipopolysaccharide) layer of Gram-negative bacteria
54
when are endotoxins released?
Released when cells die & lyse
55
how do endotoxins exert effect?
by stimulating macrophages to release toxic levels of cytokines
56
what do endotoxins activate?
blood clotting proteins and induce fever.
57
endotoxic shock:
drastic drop in blood pressure
58
cytopathic effect is
visible effects of viral infection
59
what does the cytocidal effect result in?
cell death
60
what do cytocidal viruses do?
stop host cell biosynthesis & induce cell’s lysosomes to release content
61
what is found in some infected cells?
inclusion bodies/granules Are usually viral parts (nucleic acids, proteins) to be assembled; can be diagnostic
62
infected cells may fuse to form?
multinucleate syncytium
63
some virus-infected cells form what?
interferons protect bib-infected cells
64
syncytium formation:
1. virus entry via membrane fusion 2. viral capsid enters, replication practices (viral envelope w/protiens) 3. cells fuse w/non-infected cells 4. multinucleate cell: fusion with more cells gets bigger forming syncytium
65
portals of exit:
secretion, exertions, discharges tissue that is shed
66
portal of exit is related to the?
part of the body that was infected
67
most common portal of exit:
respiratory tract and GI tract

MICRO FINAL EXAM (9 decks)

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