Ch 4: Bacteria and infection

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Ch 4: Bacteria and infection
2011-02-02 19:48:17
bacteria infection

bacteria and infection
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  1. Sphere
  2. Rod
  3. Very short rod
  4. Rod-shaped with tapered end
    Fusiform Bacillus
  5. Curved rod
  6. Spiral bacteria in which cell is rigid
  7. Spiral shaped bacteria in which cell is flexible and undulating
  8. Cocci forming 2 cell arrangement
  9. Cocci forming 4 cell arrangement
  10. Cocci forming chains
  11. Cocci forming clusters
  12. What is an opportunistic pathogen?
    Organisms that cause disease by taking advantge of a host’s increased susceptibility to infection. When the host is not especially susceptible, these organisms are not pathogenic. Infects a host susceptible to infection
  13. What is a primary pathogen?
    Those that can cause disease in individuals who are healthy. Include viruses that cause diseases such as colds and mumps and bacteria that cause disease such as typhoid fever, gonorrhea, tb, and syphilis. They have evolved mechanisms that allow them to overcome the defenses of the host and, once inside a host, to multiply rapidly. Some are restricted to humans, others infect animals or plants.
  14. What are the five requirements for infection?
    • 1. Entry
    • 2. Establishment
    • 3. Defeat the host defenses
    • 4. Damage the host
    • 5. Be transmissible
  15. Define Virulence
    Refers to how harmful a pathogen is to the host. How virulent depends on genetic factors of the pathogen. These genetic elements are often turned on only in the host.
  16. What are the three main functions of a biofilm?
    • 1. They can capture and retain nutrients, allowing continued growth which allows the bacterial population to increase in number
    • 2. They impeded uptake of antibiotics and disinfectants that are potentially dangerous to the bacteria
    • 3. They inhibit phagocytosis. The adhesion of a biofilm can also affect the host inflammatory response by attracting host defensive cells that attempt to engulf the biofilm. This results in what is referred to as “frustrated phagocytosis”, causing the formation of gigantic cells that eventually form a tough collagen capsule that inhibits new blood vessel development and interferes w/ wound healing.
  17. What is a biofilm made of?
    Bacteria adhere and grow as aggregated assemblies of cells.
  18. What is a biofilm composed of when it grows on some foregin medical device?
    • The body first coates it with a protective film which is composed of -
    • Fibronectin
    • Fibrinogen
    • Albumin
    • Immunoglobulins
    • Other proteins that serve as binding sites and receptors for bacteria.
  19. Pinocytosis
    • A type of Endocytosis. The taking in of small molecules by invagination of the cell membrane.
    • The cell membrane picks up on something it wants that's outside of it in the environment, creates a little dent or vesicle that engulfs that particle, vesicle closes off and particle is now inside the cell.
    • Is more a response of the cell rather than the cell's activity
  20. Phagocytosis
    • A type of endocytosis. Ingestion of materials into cells by means of vacuole formation.
    • Cell sees something it wants, create "false feet" (pseudopodium) which go out and engulf that material.
  21. Receptor-Mediated Endocytosis
    A type of endocytosis. Receptors on the surface of the cell bind with the extracellular material that is to be brought into the cell. Plasma membrane sinks into cell interior and a vesicle forms (like pinocytosis.)
  22. How are organisms classified?
    Biologists classify microorganism by their genus name and their species name. The genus and species names are italicized. The Genus name is always capitalized and the species name is always lower case.
  23. What size are viruses?
    0.03-0.3 microg
  24. What size are bacteria?
    0.1-10 microg
  25. What size are protazoa/fungi?
    4-40 microg
  26. What 5 things must you have to have a successful infection?
    • Entry (getting in)
    • Establishment (staying in)
    • Defeat the host defenses
    • Damage the host (can be debated b/c you can be infected w/ something that doesn’t damage you but you could be a carrier)
    • Be transmissible
  27. Pathogenicity Islands
    • A cluster of virulence genes.
    • They are carried on plasmids which are found on chromosomes.
    • Form because pathogens often carry clusters of genes whose activity results in the production of factors that increase its virulence.
  28. Quorum Sensing
    Specialized proteins in a pathogen cell called sensing proteins relay info about the cells enviro to other proteins that regulate genes controlling the transcription of virulence genes.
  29. Exocytosis
    The Reverse of Endocytosis