Medical Micro Unit 1

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Medical Micro Unit 1
2011-09-22 15:06:16

Exam 1
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  1. Pasteur
    • Vaccines
    • Swan neck flask
    • Pasteurization
  2. Koch
    • Postulates
    • Used agar to culture bacteria

    • Worked with:
    • B. anthracis
    • M. tuberculosis
    • V. cholerae
  3. Semmelweis
    • "Cadaver Particles"
    • Noticed women who used doctors when giving birth died more often than those who used a midwife.
  4. Snow
    • Father of Epidemiology
    • Showed water source was a cause of cholera
    • Contributed to formation of Germ Theory
  5. Lister
    • Found that airborn microbes were causing disease (rather than miasma)
    • Used carbolic acid as an antiseptic in gangrene patients
    • Used chloroform as an anaesthetic for surgery
  6. Leeuwenhoek
    • Father of Microbiology
    • Used a microscope to see "animacules"
  7. Henle
    • Germ Theory of Disease
    • Helped disprove spontaneous generation
  8. Koch's Postulates
    • 1. Obtain pathogen from diseased organism
    • 2. Isolate and purify
    • 3. Infect healthy model, look for symptoms
    • 4. Isolate pathogen from infected model and compare to the original
  9. Problems with Koch's Postulates (2)
    May not have an infected model

    Pathogen may leave the host
  10. Paul Ehrlich
    • Believed he could create a compound to selectively target a disease causing organism.
    • Salvarsen- arsenic based toxin for curing syphilis
    • Prontosil- Sulfide amide that targets bacteria
  11. Alexander Fleming
    • Penicillin
    • Lysozyme
  12. Enders, Weller, & Robbins
    Polio virus vaccine
  13. Pathogen
    Microbe capable of harming a normal host
  14. Signs vs Symptoms
    • Signs= Directly measured
    • Symptoms= Feeling, not quantitative
  15. Pathogenicity
    Development of disease. Measured by pathogenicity and virulence
  16. Pathogenicity vs Virulence
    • Pathogenicity- Ability of organism to cause disease
    • Virulence- measure of the severity of disease a pathogen is capable of causing
  17. Opportunistic Pathogen
    A pathogen that harms a compromised host
  18. Toxoplasma gondii
    Opportunistic pathogen that causes tumors in immunocompromised mice. Brain tumors cause them to no longer fear mice. This pathogen also attacks people with AIDS.
  19. Commensal Microorganisms
    • Helpful, but can cause disease if in the wrong place
    • Normal Flora
  20. Pili, Capsule, Flagella
    Bacteria disease causing agents
  21. Bacterial Species
    • 16S ribosome must differ by less than 30%
    • Use DNA hybridization to compare DNA samples
  22. Gram Positive
    • Purple stain
    • Thick peptidoglycan layer
  23. Gram Negative
    • Stains red/pink
    • Has thin peptidoglycan layer
    • Has outer membrane with LPS which can cause disease, even after cell dies.
  24. Autotrophs vs Heterotrophs
    • Autotrophs- use light or inorganic material for energy
    • Heterotrophs- get energy from organic molecules (most likely pathogen)
  25. Bacterial Growth Phases
    • 1. Lag Phase
    • 2. Log Phase (slower in actual host than in lab)
    • 3. Stationary Phase
    • 4. Death Phase
  26. Bacteria capable of making spores
    • Clostridium (aerobic)
    • Bacillus (anaerobic)
  27. Bordetellae
    Regulation of Gene Expression
    • (Whooping cough)
    • BVG A
    • BVG S
    • FHA
    • Express genes to become more pathogenic
  28. Plasmid Genes
    Not usually "house keeping genes", but genes for resistance and/or virulence.
  29. Transmission of Pathogens / Disease
    • Airborn & Ingestion usually require a lot of pathogen since body has natural defense
    • Sex transmission- small amount of pathogen
    • Vector born disease- require smallest dose for disease
  30. LD50 vs ID50
    LD50- Number of microbes needed to kill 50% of hosts

    ID50- Number of microbes needed to infect 50% of hosts
  31. Host Susceptibility
    • Stress
    • Nutrition
    • Age
    • Immunodeficiency
    • Genetics
  32. Exogenous Infection vs Endogenous Infection
    • Exogenous- Exposed to microbe from external source
    • Endogenous- Normal flora spreads to other part of body
  33. Primary vs Secondary Infection
    • Primary- Initially infected
    • Secondary- Pathogen inhabits, but disease is caused later after host is weakend
  34. Subclinical Infection
    Host has no apparent symptoms
  35. Nosocomial Infection
    Acquired as a result of hospitalization
  36. Focal Infection
    A local infection that causes disease in other part of the body (ex. from toxins)
  37. Parasytic
    • Parasytic- benefits at expense of host
    • Commensal- benefits but doesn't harm host
    • Symbiotic- both benefit
  38. Advantages of Normal Flora
    • Vitamin K
    • Riboflavin
    • B12
    • Steroid breakdown for bile production
    • Competes w/ infecting species
  39. Sterile Organs
    • Blood
    • Kidney
    • Lungs
    • Peritoneum
    • Bladder
    • Larynx
  40. Bacteremia vs Septicemia
    • Bacteremia- presence of bacteria in blood
    • Septicemia- bacteria reproducing in blood
  41. Lysosome
    • low pH
    • lysozyme
    • proteinase
  42. Natural Killer Cell
    • Respond to interferons, cytokines
    • Granules with perforin and granzyme
    • Cause apaptosis
  43. Toll Receptors
    Evolutionarily long lived (PAMP)

    • lipoproteins
    • dsRNA
    • LPS
    • flagella
    • unmethylated CpG DNA
  44. Compliment
    • 1. Chemotaxis
    • 2. Opsonization
    • 3. Membrane attack complex (directly kills cell via membrane holes)
  45. Anaphylatoxin
    Allergy related reaction of compliment
  46. Bacteria that breakdown blood clots
    • S. aureus- coagulase
    • Streptococcus- streptokinase
  47. Inflammation
    • Cytokines and compliment trigger it
    • Heat, swelling, increase in blood flow, chemotaxis
  48. T H1 Cell
    Amplify inflammatory response, release cytokines to activate macrophages and other phagocytic cells.
  49. T H2 Cell
    Activates B Cells
  50. Allergy Related Immune Cells
    • Mast Cells
    • Basophils
    • Eosinophils
  51. IgM
    • IgM- Ab of primary response (large, 10 binding sites)
    • IgG- Ab of secondary exposure (small)
    • IgA- Ab secreted in body fluids
    • IgE- Ab associated with allergies
  52. Phagolysozyme
    • Digests proteins to be incorporated into MHC and sent to cell surface.
    • MHC1 intracellular
    • MHC2 phagocytosis
  53. MHC1 / MHC2 reception
    MHC2 -> TCR -> T H1 Cell -> Cytokines

    MHC1 -> TCR -> TC Cell -> Perforin granzyme (target cell lysis)
  54. Sjogren's Syndrome
    Autoimmune disease. Body attacks glands that produce sweat and tears.
  55. B Cell -> Plasma Cell
    T H2 Cell recognizes MHC2 antigen of B Cell. Then T H2 Cell produces cytokines which activates B Cell.
  56. Bacteria Superantigens
    Cause non-specific activation of T Cells resulting in cytokine release and over-inflammation.
  57. Passive Immunity
    Natural vs Artificial
    Transfer of antibodies to unimmunized person. No lasting immunity (memory).

    • Natural- Ex. Antibodies in breast milk
    • Artificial- Ex. Tetanus antitoxin injection
  58. Active Immunity
    Natural vs Artificial
    Antibodies are produced, the immune system "remembers" the antigen

    • Natural- Exposed to pathogen and then produce own antibodies
    • Artifical- Vaccination
  59. Requirements of a Good Vaccine (4)
    • 1. Effective / Last a long time
    • 2. Safe from side effects
    • 3. Stable, able to get it to people
    • 4. Low cost
  60. Types of Vaccines (5)
    • 1. Microbe w/ artificially reduced virulence
    • 2. Microbe w/ naturally reduced virulence (ex. similar organism)
    • 3. Killed cells (aka Inactivated)
    • 4. Subcellular fractions (toxoids, capsules, surface peptides)
    • 5. Genetically engineered vaccines
  61. New Methods of Vaccine Delivery
    • Skin patches
    • Edible plant/fruits w/ vaccine
    • Make attenuated vaccine via knockout mutant
    • DNA Vaccine- inject DNA into muscle tissue
    • Anti-idiotype Antibodies
  62. Anti-idiotype Antibodies
    These are antibodies that bind to the variable region of other antibodies
  63. Factors Influencing the Success of Vaccination
    • 1. Age
    • 2. Population Density
    • 3. Risk of infection must outweigh risk of vaccination
  64. Identifying Pathogen Infection
    • 1. Find microorganism or product of it
    • 2. Find evidence of the patient's immune response to the pathogen
  65. Benefits of:
    Bright Field Microscopy
    Dark Field Microscopy
    • Bright Field- useful for detecting protozoa
    • Dark Field- useful for viewing motile bacteria
  66. Acid Fast Test
    • Acid Fast = pink
    • Not Acid Fast= blue/purple
  67. ELISA
    • Enzyme Linked Immunosorbant Assay
    • Use ELISA plate lined with antibody. Add antigen attached to enzyme. Also add substrate. If antibody - antigen react, the enzyme will activate producing a colored dye.
  68. Western Blot
    • Used to test false positive from ELISA
    • Separates proteins (tagged with fluorescent marker) based on size.
  69. Latex Agglutination
    Latex beads bound to multiple antibodies. When they bind to antigen they agglutinate and precipitate out.

    *Test for syphilis, strep throat, pregnancy
  70. Immunodiffusion
    • Looking for antibody, not antigen
    • 5 wells. Antigen in the middle, control in two of them, patient sample in the other two. Look for patterns in the diffusion of antibody.
  71. Compliment Fixation Text
    • Detects antibodies using compliment
    • Compliment is activated by Antibody-Antigen complex. If this complex is present, it attracts compliment so that it won't lyse RBC
  72. Beta Lactam Antibiotics
    • Target cell wall synthesis
    • Bind to pennicilin-binding proteins to prevent synthesis of cell wall.
    • Not very effective against Gram negative
    • Not at all effective against microbes without cell wall
  73. Vancomycin
    A Glycopeptide

    Stops cell wall synthesis
  74. Bacitracin
    A Glycopeptide

    A topical cream that interferes with dephosphorylation, a step in cell wall synthesis, and inhibits recycling of a lipid carrier that moves peptide precursor through the cell membrane to the cell wall.
  75. Isoniazid
    Targets acid fast cell walls

    Inhibits synthesis of mycolic acids
  76. Ethambutol
    Targets acid fast cell walls

    Inhibits arabinogalactan synthesis.

    Arabinogalactan is found between mycolic acid layer and peptidoglycan
  77. Cylcoserine
    Targets acid fast cell walls

    Inhibits a unique peptide that is responsible for the crosslink in acid fast cell walls
  78. Polymixin
    Destabilizes cell membranes

    Topical cream that effects cell membranes. These are cyclic polypeptides that insert into the cell membrane to increase permeability.
  79. Aminoglycosides
    End in -mycin

    Bind irreversibly to 30S ribo protein. Causes early release of mRNA
  80. Tetracyclines
    Binds reversibly to 30S. Inhibits aminoacyl-tRNA
  81. Oxazolidinones
    Targets 30S ribo protein to inhibit formation of initiation complex
  82. Chloramphenicol
    Used as a last resort. Can be toxic to bone marrow cells

    Targets 50S ribo unit. Binds peptidyl transferase so no peptide elongation.
  83. Macrolides
    Ex. Erythromycin- binds to a different site of peptidyl transferase. Given to decrease inflammation.
  84. Linkosamide
    Binds to a different site of 50S ribo
  85. Streptogramins
    Prevent polypeptide elongation. Cause premature release

    Quinupristin & Dalfopristin work synergistically
  86. Quinolones
    Nucleic Acid Synthesis Inhibitor

    Inhibit DNA Gyrase
  87. Rifampin & Rifabutin
    Nucleic Acid Synthesis Inhibitor

    Semisynthetic. Inhibit DNA dependent RNA polymerases. Mainly used for TB.
  88. Metronidazole
    Nucleic Acid Sythesis Inhibitor

    Mainly for anaerobic bacteria or protozoa

    Works as prodrug. Given in the inactive form, activated by enzyme in the pathogen.

    Targets nitroreductase
  89. Sulfonamides
    Folic Acid Synthsis Inhibitor

    Compete w/ p-aminobenzoic acid as substrate in folic acid synthesis mechanism
  90. Trimethoprim
    Folic Acid Synthesis Inhibitor

    Inhibits key enzyme, dihydrofolate reductase, in folic acid synthesis mechanism