Unusual Bacteria & Intro. to Pathogenesis Flashcards Preview

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Flashcards in Unusual Bacteria & Intro. to Pathogenesis Deck (18)
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name the aerobic and anaerobic members of the Actinomycetalesfamily 

  • aerobic:
    • Mycobacterium
      • M. tuberculosis (TB)
      • M. leprae (leprosy)
      • M. marinum (wound infxns)
    • Nocardia
  • anaerobic:
    • Actinomyces


explain why the cell wall in mycobacteria is different from other bacteria

  • mycolic acids
    • "waxy" outer coat
    • results in slow growth (longer incubation times; chronic infxns)
      • limited penetration of nutrients leads to slow growth
    • more difficult to stain; Gram stain does not work reliably
  • arabinogalactan


describe acid-fast staining (Ziehl-Neelsen method) and which bacteria it is used for (2)


describe bacterial species without a cell wall

Mycoplasma spp.

  • smallest prokaryotes capable of independent growth
    • adaptation: sterols in membrane
  • 5 families: Mycoplasmatoceae most significant
  • 2 key species:
    • Mycoplasma
    • Ureaplasma


describe bacteria that have unusual lifecycles (2)

Chlamydia and Rickettsia sp. 

  • cannot survive outside of living host cell
  • cannot be cultured on laboratory media
  • small enough to pass through usual bacteriological filters
  • Gram stain isn't normally used: tissue stains e.g. Giemsa


describe the biology of the unusual lifecycle bacteria

  • obligately intracellular
    • dependent on host for ATP and NAD
      • can't synthesize ATP or reoxidize NAD
      • no detectable flavoproteins or cytochromes
    • no peptidoglycan cell wall
    • genus specific LPS
  • Chlamydia: complex and unusual life cycle with 2 developmental forms
    • elementary bodies (EB): infectious form
    • reticulate bodies (RB): replicative form


name the 2 developmental forms of Chlamydia

  • elementary bodies (EB): infectious form
  • reticulate body (RB): replicative form


describe the basic properties of algae (eukaryotes)

  • unicellular (microscopic)
    • diatoms, dinoflagellates
  • multicellular (macroscopic)
    • seaweeds
  • mostly aquatic; important for primary productivity and as a direct food source
  • cellulose walls
  • photosynthetic
    • contains chloroplast and chlorophyll


list the microbial factors vs the host immune resposne that contribute to the clinical signs and symptoms of an infxn

  • microbial factors:
    • physical impact of growth in a specific location/tissue
    • damage due to:
      • enzymes
      • toxins
      • cellular components/products
    • ability to sense and respond to environment
  • host immune response
    • cytokines, interleukins, respiratory burst enzymes, etc.


describe the steps in the establishment of infection


describe an infection with gonorrhea 

  • acute infection
    • factors that cause damage:
      • microbial
        • lipooligosaccharide
        • antigenic variation
      • inflammatory response


describe true vs. opportunistic pathogens 


define a true pathogen

  • able to cause infxns in a healthy host, with intact defenses
  • "virulent" due to production of:
    • toxins
    • adhesins
    • enzymes
    • capsules
    • evasion of immune system: antigenic variation, etc.


who is at risk for opportunistic infxns?

  • host with damaged or deficient defenses (acquired, infection, etc.)
  • situations that can predispose to an opportunistic infection tend to be:
    • weak/malfunctioning immune system
    • disruptions to normal flora
    • breach of barriers (skin, mucosa)
  • opportunistic pathogens are often:
    • microbial flora of host (endogenous)
    • environmental fungi


name the conditions that predispose to opportunistic infections

  • diabetes mellitus
  • renal failure
  • hematological malignancy
  • infectious diseases (e.g. tuberculosis)
  • autoimmune disorders
  • chronic glomerular disease
  • immunosuppressive therapy


describe the different types of persistent infxns

  • chronic (timeframe)
    • long duration
    • develops slowly
    • shedding (intermittently) continues
  • latent (feature of the microbe)
    • genome/pathogen maintained in host without active microbial replication


describe Treponema pallidum and syphillis (chronic infxn)


describe Mycobacterium tuberculosis and TB (latent infxn)