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MICRO FINAL EXAM > Ch.15 Microbial Pathogenesis > Flashcards

Ch.15 Microbial Pathogenesis Flashcards

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
Q

extracellular enzymes:
PROTEASES

A

destroy host proteins

IgA protease

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26
Q

antigenic variation

A

alteration of pathogen surface proteins

posses alternate genes

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27
Q

invasins

A

pathogen surface proteins that rearrange actin filaments

induces membrane ruffling

pathogen engulfed into the cell

28
Q

penetration into the host cell cytoskeleton:

A

some pathogens enter cells of the host using filaments of the cystolention

29
Q

what is an example of a common means of entry?

A

actin filaments

30
Q

pathogen damage to host cells by:

host nutrients

A

using host nutrients

pathogen acquire host iron via siderophores

Iron (Fe) Chelator

31
Q

pathogen damage to host cells by:

damage in the area of infection

A

causing direct damage in the vicinity of infection

intracellular pathogens

ex: viral infection

32
Q

pathogen damage to host cells by:

production of toxins

A

production of toxins; transported by blood, lymph

inhibit protein s ytehsis

Disruption of membrane

33
Q

pathogen damage to host cells by:
induction of hypersensitive reactions

A

Induction of hypersensitivity reactions

overproduction of cytokines

34
Q

exotoxins are secreted to what?

A

to the surrounding environment

35
Q

what is the action of exotoxins:

A

destroy specific host cell structures or inhibit metabolic functions

can be very lethal

36
Q

types of exotoxins:

A

A-B toxins

Membrane-disrupting Toxins

Superantigens

37
Q

describe the components of exotoxins

A

water-soluble proteins (many are enzymes

most are plasmid-based or inpageges (lysogenic conversion)

38
Q

what do toxoid forms of antitoxins do?

A

provide immunity

39
Q

A-B toxins consist of what?

A

A: an active enzyme component
B: cell binding component

40
Q

A-B Toxin:

DIPHTHERIA TOXIN

A

Corynebacterium diphtheriae

inhibits protein synthesis

phage carries tox gene

41
Q

A-B Toxin:

Botulism Toxin

A

Clostridium botulinum neurotoxin;

prevents nerve impulses to muscles;

causes flaccid paralysis.

42
Q

A-B Toxin:

Tetanus Toxin

A

Clostridium tetani neurotoxin tetanospasmin;

blocks inhibitory nerve impulses to
muscles;

causes spasmodic contractions.

43
Q

A-B Toxin:

Vibrio Enterotoxin

A

Vibrio cholerae cholera toxin; causes cellular

secretion of fluids & electrolytes ->
severe diarrhea & dehydration

44
Q

membrane-disrupting toxin:

A

cause lysis of host cells by disrupting the plasma membrane

45
Q

how does membrane-disrupting toxin cause lysis of host cells by disrupting the plasma membrane?

A

forming protein channels in the membrane or by disrupting phospholipids

46
Q

Leukocidins

A

kill phagocytic white blood cells

47
Q

hemolysins:

A

kill red blood cells

48
Q

super antigens stimulate

A

intense immune response of T cells

49
Q

T cells stimulated to produce:

A

cytokines

regulate immune response

50
Q

what happens due to excessive cytokine levels?

A

enter the bloodstream and induce symptoms

can lead to shock & death

51
Q

Erythrogenic toxins (Streptococcus pyogenes):

A

damage blood capillaries under the skin

Cause: rash; scarlet fever.

52
Q

Staphylococcal enterotoxin

A

superantigen

(S. aureus)

53
Q

what are endotoxins?

A

are the lipid portion (lipid A) of the
LPS (lipopolysaccharide) layer of Gram-negative
bacteria

54
Q

when are endotoxins released?

A

Released when cells die & lyse

55
Q

how do endotoxins exert effect?

A

by stimulating macrophages to
release toxic levels of cytokines

56
Q

what do endotoxins activate?

A

blood clotting proteins and induce fever.

57
Q

endotoxic shock:

A

drastic drop in blood pressure

58
Q

cytopathic effect is

A

visible effects of viral infection

59
Q

what does the cytocidal effect result in?

A

cell death

60
Q

what do cytocidal viruses do?

A

stop host cell biosynthesis &
induce cell’s lysosomes to release content

61
Q

what is found in some infected cells?

A

inclusion bodies/granules

Are usually viral parts (nucleic acids, proteins) to be assembled;

can be diagnostic

62
Q

infected cells may fuse to form?

A

multinucleate syncytium

63
Q

some virus-infected cells form what?

A

interferons
protect bib-infected cells

64
Q

syncytium formation:

A
  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
Q

portals of exit:

A

secretion, exertions, discharges tissue that is shed

66
Q

portal of exit is related to the?

A

part of the body that was infected

67
Q

most common portal of exit:

A

respiratory tract and GI tract

MICRO FINAL EXAM (9 decks)

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