Bacterial and Fungal Pathogenesis Flashcards Preview

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Flashcards in Bacterial and Fungal Pathogenesis Deck (16)
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summarize the important bacterial enzymes


describe the 2 components of exotoxins and the 3 classes


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


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


describe adhesion and colonization

  • 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)


describe tissue tropism and name 2 examples


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

  • 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


describe biofilm

  • 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.


name 3 advantages of biofilm formation

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


describe microbial acquisition of iron


summarize the strategies for acquisition of iron by microorganisms 


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

  • 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


describe how microorganisms survive in phagocytic cells

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


describe evasion via antigenic and phase variation

  • 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


describe the spread and dissemination of microorganisms


give an example of an exotoxin