Chapter 15 Flashcards

1
Q

Pathogenicity

A

The ability to cause disease

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2
Q

Virulence

A

The degree of pathogenicity

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3
Q

Portals of entry (name 3)

A
  • Mucous membranes - Skin - Parenteral route
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4
Q

Parenteral route

A

Deposited directly into tissues when barriers are penetrated

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5
Q

Most pathogens have a preferred _______ __ _____.

A

portal of entry

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6
Q

ID50

A

Infectious Dose for 50% of a sample population

Measures virulence of a microbe

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7
Q

LD50

A

Lethal Dose for 50 % of a sample population

Measures potency of a toxin

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8
Q

Almost all pathogens attach to host tissues in a process called ________

A

adherence (adhesion)

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9
Q

Adhesions (_____) on pathogen bind to _______ on host cells. Name two examples.

A

(ligands)

receptors

  1. Glycocalyx
  2. Fimbriae
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10
Q

After adherence microbes form ______

A

biofilms

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11
Q

Capsules: Glycocalyx around cell walls. What does this impair? Examples?

A

Impair phagocytosis

Streptococcus pneumoniae - pnuemonia

Haemophilus influenzae - pneumonia and meningitis

Bacillus anthracis - anthrax

Yersinia pestis - plague

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12
Q

M protein

A

Cell wall component; resists phagocytosis

Example: streptococcus pyogenes

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13
Q

Opa protein

A

Cell wall component; allows attachment to host cells

Example: neisseria gonorrhoeae

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14
Q

Waxy lipid

A

Cell wall component; (mycolic acid) resists digestion

(mycobacterium tuberculosis)

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15
Q

Coagulases

A

Coagulate fibrinogen

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16
Q

Kinases

A

Digest fibrin clots

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17
Q

Hyaluronidase

A

Digests polysaccharides that hold cells together

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18
Q

Collagenase

A

Breaks down collagen

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19
Q

IgA proteases

A

Destroy destroy IgA antibodies

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20
Q

Antigenic Variation

A

Pathogens alter surface antigens (and antibodies are rendered ineffective)

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21
Q

Invasions

A

Surface proteins produced by bacteria that rearrange actin filaments of the cytoskeleton (cause membrane ruffling)

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22
Q

Pathogens use _______ to move from one cell to the next (shigella and lsiteria)

A

actin

23
Q

_______ is required for most pathogenic bacteria

A
24
Q

Siderophores

A

Proteins secreted by pathogens that bind iron more tightly than host cells

25
Q

How does direct damage work?

A
  • Disrupts host cell function
  • Uses host cell nutrients
  • Produces waste products
  • Multiplies in host cells and causes ruptures
26
Q

Toxins

A

Poisonous substances produced by microorganisms

Produce fever cardiovascular problems, diarrhea, and shock

27
Q

Toxigenicity

A

Ability of microorganism to produce a toxin

28
Q

Toxemia

A

Presence of toxi in host’s blood

29
Q

Intoxications

A

Presence of toxin without microbial growth

30
Q

Exotoxins

A

Proteins produced and secreted by bacteria

-Soluble in bodily fluids; destroy host cells and inhibit metabolic functions

31
Q

Antitoxins

A

Antibodies against specific exotoxins

32
Q

Toxoids

A

Inactivated exotoxins used in vaccines

33
Q

A-B toxins

A

Exotoxin

contain an enzyme component (A part) and binding component (B part)

(diphteria toxin)

34
Q

Membrane-disrupting toxins

Name 3

A
  • lyse host cells by disrupting plasma membranes
  1. Leukocidins
  2. Hemolysins
  3. Streptolysins
35
Q

Leukocidin

Endo or Exo toxin?

A

Kill phagocytic leukocytes; Exotoxin

36
Q

Hemolysis

Endo or Exo -toxin?

A

Kills erythrocytes by forming protein channels; Exotoxin

37
Q

Streptolysins

Endo or Exo -toxin?

A

hemolysins produced by streptococci; Exotoxin

38
Q

Superantigens

Symptoms?

A

Cause intense immune response due to release of cytokines from host cells (T cells)

Causes symptoms of fever, nausea, vomiting, diarrhea, shock, and death

39
Q

Genotoxins

A

Damage DNA (causing mutations, disrupting cell division, and leading to cancer)

40
Q

Lipid A

Endo or Exo -toxin?

A

Portion of lipopolysaccharides (LPS) of gram-negative bacteria

41
Q

What is released during bacterial multiplication and when gram-negative bacteria die?

A

Endotoxins

  • Stimulate macrophages to release cytokines
  • Cause disseminated intravascular coagulation
42
Q

What may carry genes for toxins, production of antibiotics, and enzymes?

A

Plasmids

43
Q

Lysogenic conversion

A

Changes characteristics of a microbe due to incorporation of a prophage

44
Q

Cytopathic Effects (CPE)

A

Visible effects of a viral infection on a cell

45
Q

Examples of CPEs?

A
  • Stopping cell synthesis
  • Causing cell lysosomes to release enzymes
  • Creating inclusion bodies in the cell cytoplasm
  • Fusing cells to create syncytium
  • Changing host cell function or inducing chromosomal changes
  • Inducing antigenic changes on the cell surface
  • Loss of contact inhibition in the cell, leading to cancer
  • Producing interferons to protect uninfected cells
46
Q

How do Fungi act as a pathogen?

A
  • Toxic metabolic products
  • Provoke an allergic response
  • Trichothecene toxins inhibit protein synthesis
  • Proteases modify host cell membranes
  • Capsules prevent phagocytosis
47
Q

Three main types of ‘pathogenic’ fungi

A
  • Ergot
  • Aflatoxin
  • Mycotoxins
48
Q

Ergot

A

Alkaloid toxins that cause hallucinations

49
Q

Aflatoxin

A

Carcinogenic toxin produced by aspergillus

50
Q

Mycotoxins

Name two

A

Produced by mushrooms and are neurotoxic

Phalloidin and Amanitin

51
Q

Protoza avoid host defenses by what 3 methods?

A

Digesting cells and tissue fluids

Grow in phagocytes

Antigenic variation

52
Q

Portals of Exit

A
  • Respiratory tract
    • Coughing and sneezing
  • Gastrointestinal tract
    • Feces and saliva
  • Genitourinary tract
    • Urine; secretions from teh penis and vagina
  • Skin
  • Blood
    • Anthropods that bite; needles or syringes
53
Q
A