Bacterial and Fungal Pathogenesis Flashcards Preview

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Flashcards in Bacterial and Fungal Pathogenesis Deck (16)
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1
Q

summarize the important bacterial enzymes

A
2
Q

describe the 2 components of exotoxins and the 3 classes

A
3
Q

give examples of toxins and the producing organisms (tetanus toxin, pertussis toxin, TSST, pyrogenic exotoxins)

A
4
Q

describe the features (potency, used as vaccine, specificity of action, and how its released) associated with exotoxins vs endotoxins

A
5
Q

describe adhesion and colonization

A
  • specialized adhesion structures (e.g. pili, fimbriae)
  • 2 types of adhesion:
    • nonspecific
    • specific
  • expression of adhesion structures = dependent on environmental conditions
  • role: prevent removal
    • e.g. urinary tract: would be “flushed” out by urinary flow
  • can involve specialized or non-specialized structures (e.g. capsule)
6
Q

describe tissue tropism and name 2 examples

A
7
Q

describe how a range of diffrerent bacterial surface structures can be used for adhesion

A
  • external to cell wall/outer membrane
    • fimbirae/common pili
    • capsules & slime layer
  • integral part of cell
    • teichoic and lipoteichoic acids
    • LPS
    • outer membrane proteins and porins
  • adhesins: component on bacterial cell used for attachment to a tissue, cell or surface
  • receptors: host cell molecule that the bacterial adhesin attaches to
8
Q

describe biofilm

A
  • attachment to surface, replication and microbial production of sticky expolymeric substance (EPS) coating
  • the default mode of growth
  • estimated >70% of all human infxns including:
    • endocarditis, osteomyelitis, UTIs, STIs, pneumonia, peptic ulcers, etc.
9
Q

name 3 advantages of biofilm formation

A
  1. better resistance to antimicrobial agents
  2. resist host immune response
  3. act as reservoir
10
Q

describe microbial acquisition of iron

A
11
Q

summarize the strategies for acquisition of iron by microorganisms

A
12
Q

describe evasion of microbes and intracellular survival & cell-cell spread

A
  • intracellular phase for growth can be:
    • essential (obligate): e.g. Chlamydia trachomatis
    • at specific points (facultative): e.g. Salmonella
    • not necessary at all: e.g. Vibrio cholerae
13
Q

describe how microorganisms survive in phagocytic cells

A
  • prevent fusion of phagosome and lysosome
  • escape from phagolysosome
  • resist/inactivate lysosomal enzymes
  • enzymatically inactivate harmful oxygen species
14
Q

describe evasion via antigenic and phase variation

A
  • antigenic variation = changes in pathogens’ recognizable surface antigens
  • recognition and eradication more difficult
  • also possible: phase variation (on/off)
  • 2 levels:
    • genetic
      • recombination; mutation
    • epigenetic:
      • via DNA methylation
15
Q

describe the spread and dissemination of microorganisms

A
16
Q

give an example of an exotoxin

A