Last Lecture Test 2011

  1. 3 Group curviform bacteria
    • Vibrio-comma
    • Heliobacter-spirochette
    • Campylobacter-spiral or vibio-S shaped like eagle wings
  2. Most common Vibrio Cholera
    • causes cholera
    • top 7 causes of morbidity and mortality
    • get by ingestion
    • outbreaks seen along Gulf of Mexico
    • in shellfish
    • requires lrg # of organisms (10 to the 8)cells
  3. The cholera disease due to
    • production of endotoxin-cholera toxin(CT)
    • make s body secrete secretory diarrhea
    • and rice water stool
  4. Symptoms:
    • loss of 50% of body weight
    • loss of 1 liter of fluid
    • loss of blood volume due to diarheaa
    • acidosis due to bicarbonate loss
    • potassium depletion
    • Death can occur in 48 hrs if not treated
    • mortality rate 55%
  5. Diagnosis and Treatment:
    • Oral rehydration therapy
    • oral antibiotics-tetracycline and trimethoprin-sulfa
  6. Prevention:
    • Proper sewage disposal and water purification
    • vaccines contaning kileed cholera vibrios-only protects 6 months or less
    • oral vaccine w/ live attenuated vibrios
  7. Campylobacter jejuni:
    one of most imp causes of gastroenteris worldwide
  8. Symptoms:
    • 1-7 days after ingsetion-headache, fever,ab pain, diarheaa
    • the bacteria cause heat labile enterotoxin called CJT(cmp jejuni toxin) make diarheaa
    • can lead to neurological disease -Guillain Barre syndrome
  9. Diagnosis, Treatment and Prevention:
    • Daignosed by fecal samples containing curbed rods
    • Treated by rehydration and electrolyte replacement
    • Prevented by-no vaccines, prevented only by strict adherence to sanitary control measures for milk and food productiona nd storage
  10. Helicobacter pylori:
    • causes gastritis and causes 90% of stomach and duodenal ulcers
    • cofactor in dev of stomach cancer-adenocarcinoma
    • spirochettes
  11. Helicobacter info:
    • discovered in stomach biopsies-J.Robin warren and Barry Marshall-swallowed microoragnisms to prove caused gastritis
    • awarded Nobel Prize in 2005
    • transmitted by oral-oral or fecal-oral by people
    • also by mecahnical vectors-house flies
    • been suggested disease is zoonosis
    • the receptor that oragnism attaches to same as found on RBC of type O-so type O blood have 1.5-2 times chances higher of stomach ulcers
    • bacteria produce urease
  12. Diagnosis and Treatment:
    • from biopsy specimens
    • testing for pH changes
    • urea breath test
    • treated w/ drugs-Tagament, Zantac
  13. Family Rickettsiaceae
    • 23 species
    • Rickettsia, Ehrlichia, Orientia
    • collectively known as Rickettsias
    • disease caused called rickettsioses
    • obligate intracellular parasites
    • must get ATP from host
    • one of smallest bacteria cells
    • gram-cell wall
    • reproduce by binary fission

    • contaion RNA and DNA
    • hv meatabolic patheay for synthesis and growth
    • are pleomorphic rods or coccobacilli-short fat
    • spend part of life in arthropods-ticks, fleas, louse
    • bacteria enter and mutilpy in endothelial cells and blood vessels, necrosis of vascular lining
    • cause rash, edema, hypotension, gangrene, clotting in brain, stupor, neurological symptoms
  14. Treatment:
    Tertacycline, Chloramphenicol
  15. Differintaition:
    • based on clinical features and epidemiology
    • 1) Typhus group
    • 2)Spotted fever group
  16. 2 types
    • 1)Epidemic Typhus-Rickettsia prowazekii
    • named in honor of Howard Ricketts and Stanislaus Prowazek
    • carried only by humans and lice are the reservoirs
  17. Symptoms Treatment and Prevention:
    • Symptoms-fever, chills, rash all over trunk arms and legs
    • 40-60% mortality rate in patients over 50
    • years later in human reservoirs from areas of typhus-can have milder recurring form-Brill-Zinsser
    • Treatment-Tertacycline, Chloramphenicol, Environmental control, antilouse shampoo, vaccination
  18. 2nd kind:
    • Rocky Mountain Spotted Fever-1st seen in Rocky Mt of Montana and Idaho
    • seen in Southeast, eastern seaborn regions-highest in NC
    • oragnism is Rickettsia rickettsii
    • by hard ticks-dog ticks
    • dogs mmajor vector in southeast
  19. Symptoms:
    • after2-4 days incubation-fever, chills, distictive spotted rash, causes cardiovascular disruption and prob w/ central nervous system
    • Death in 20% untreated, 5-10% treated
  20. Diagnosis:
    when a cluster of symptoms are seen-fever, rash, plus contact w/ dog w/ ticks, or exposure in spring or summer
  21. Treatment:
    • Tetracycline
    • New vaccine-w/ rick. grown in chick embrypo and fed to humans
    • Prevent by wearing protective clothing, insect repellent, and removing ticks
  22. Chlamydia:
    • Obligate intracellular
    • small
    • gram-negative
    • pleimorphic
    • diff in their life cycle
    • alternate bet 2 stages-
    • 1) Elementary body- meatbolically inactive, infectious form relaesed by host, protective envelope
    • 2) Reticulate body-noninfectious body, stays in host, completes life cycle-makes more elemntary bodies-gets all energy from host cell
  23. Chlamydia trachomatis
    • causes 2nd most sexually transmitted disaese-NGU-chlamydiosis or chlamydia urethristis
    • and neonatal disease and ocular infection trachoma
  24. Disease of Eye:-2 forms
    • 1) Ocular trachoma-cuses blindness-infected upper inner of eye
    • 2) Inclusion conjunctivitis-5-12 days after birth, can be treated w/ eye drops
  25. Sexually transmitted disease:
    • Humans only host
    • carried in 10% of people
    • 70% women carry and hv no symptoms
    • 10% men same as above
    • NGU-in males mimics ghonorheaa
    • in women have cervicitis, white drainage, endometritis, salpingitis, pelvic inflamm. disaese(PID)
    • Lymphogranuloma venereum-severe disfiguring disease of genitalia and anus
  26. More facts:
    • new genus-Chlamydiophila-obligate parasite used to be included in Chlamydia
    • Chlamydiophilia pnemoniae-causes atypical pneumonia, sever reaction in asthmatic patients
    • some evidence linked to heart disease
  27. Mycoplasm:
    • smallest self replicating microorganism
    • no cell wall
    • highly pleimorphic
    • NOT strict parasites-grow in cell free media
    • fstidious need complex media containing special lipids
  28. Mycoplasma pneumoniae:
    • most primary cause of PAP-primary atypical pneum.
    • transmitted in droplets-usually crowded ares-familes, students, military
    • selctively binds to receptors in respiratory epithelium-inhibits action of cilia
    • first symptoms do not suggest pneum.-fever, sore throat
    • most patients don't dev. acute illness so disease called walking pneum.
    • only 3-105 people exposed get infected-fatalities rare
  29. VIRUSES-chapter 6
    • Most prominent emerging microbes
    • resp for 50% new outbreaks
    • sars, west nile, hiv, etc
  30. Virology
    Search for elusive viruses
  31. Diff. Viruses:
    • tobacco mosaic virus-1st stuidied, found the filtrate, not leaf had the infgection-coined "contagios living fluid"-filterable viruses
    • Foot and Mouth disease-cattle disease-filterable
    • Yellow fever-affects humans by mosquitos
    • Rabies and cow pox do not pass through filters
    • Fliterable viruses just knwon as Viruses
    • Bacteriophages are viruses that eat bacteria-phages
    • all living organisms subject to viruses
    • the relationship is specific (receptor mediated)
  32. Properties of Viruses:
    • obligate intracellular
    • ultramicroscopic size
    • not cells
    • do not fufill life independently
    • inactive outside host
    • geometric-can be crystalized
    • basic structure-coat of protein(capsid) surrounding nucleic acid core
    • acid cn be either DNA or RNA-not both
    • can be double or single stranded
    • att. to host cell necc for infection
    • cant synthesize own proteins
    • lacks enzymes for metabolic activities
  33. Dev of Virology
    • 2 events:
    • invention of electron microscope
    • polio epidemic--Salk made vaccine-inactivated virus-cant be repicated
    • 2nd vaccine by Sabine-attenuated vaccine-replication greatly reduced
  34. Structure of Virus:
    • Helical
    • Isocahedron-20 triangular faces and 12 corners
    • bacteriophages shaped liek spaceships-called complex
  35. Viruses:
    • Have no nucleus, cytoplasm, or organelles
    • Have DNA OR RNA as viral genome
    • Have capsid-made of identical protein subunits called capsomeres
    • The amount of capsomeres make up the capsid- ex-Hepres has 162 capsomeres
  36. More virus info:
    Nucleocapsid=Nucleic acid + the capsid
  37. The envelope:
    • Some have this-encases the nucleocapsid
    • acquired when leaving host cell-"budding"
    • viral cells insert into host cell membrane before virus buds from the cell-so wehn leaves it takes host cell membrane with it
  38. Spikes
    • in some viruses-influenza-thses are proteins project from the envelope-help attache to host cell
    • att to host cell necc. for virus to infect
    • if envelope virus loses envelope-no longer can infect
  39. Virion:
    A complete infectious virus
  40. Other subsatnces in Virus Particle
    • Ploymerases-assemble DNA and RNA replicases that copy RNA
    • Revererse Transcriptase-synthesizes DNA from RNA
  41. Viral classification:
    • Either plant, animal, or bacterial
    • either DNA or RNA
    • helical or icosahedron viruses
    • main criteria used:structure, chemical makeup, similarities in genetic makeup
    • 2 superfamilies of viruses are DNa and RNA viruses
    • viridae-latin root for name for virus families
  42. Host range
    • rEFERS TO WHAT organisms or hosts the virus can infect
    • based on structure of viral capsid or envelope(most hv narrow range)
    • when in host most can only infect specific tissue-tissue tropism
    • if cell doenst hv app. receptor for virus to attach-virus cant infect
  43. Viral Replication:
    • 1) attachement-no attraction, random, via receptor on host membrane
    • 2) penetration-virus injects genome in host cell-lysozyme involved
    • 3) biosynthesis-viral nucleic acid relicates-capsid proteins made, eclipse period is when no new virions are detectable w/in host celll
    • 4) maturation/assembly-new virions assembled in step by step process
    • 5) release/lysis-new virions leave cell, lysozyme involved
  44. Phages:
    • Lysogenic(temperate)phages-go into host, don't replicate, as host cell replicates, phage passes to daughter cells
    • Lytic-enters host cell, starts replicating, then bursts from host cell
    • Burst time-the time from attachemnet of phage to release of new virions(20-40 min)
  45. More:
    Burst size-# of virions emerge from host cell(50-200)
  46. Animal Viruses:
    • Replication is 5 step process but diff in animals
    • in animals:
    • 1) attachment-att site located all over the virus capsid-not just the tail as in phages
    • 2) penetration-entire virus enters-not just nucleic acid as in phage
    • Uncoating-removal of capsid-genome take s place in cytoplasm of host cell
    • 3) biosynthesis-can be in cytoplasm for capsid synthesis or nucleus for nucleic acid synthesis
    • 4) maturation-assembly into new virons
    • 5) release-some viruses destroy host cells as break out-others bud from host cell membrane
    • enveloped viruses bud from host cell and aquire their envelope this way
  47. in RNA Viruses:
    • can be positive RNA(sense RNA)-acts directly on mRna and directs protein synthesis
    • OR negative RNA(antisense RNA)-RNA polymerase carried by virus to synthesize positive RNA strand-directs protein sythesys
    • the antisense RNA genomes made from the mRna
  48. Retroviruses:
    • RNA viruse-like HIV
    • carry reverse transcript-makes complimentary copy of DNA from viral RNA-viral DNA now integrates host cell, now called PROVIRUS-in latent stage
  49. More:
    • Latency is period where host doesnt see virus so no immune response, but no viral rep. either, and if host undergoes mitosis, then integrated prophage does to
    • Soemtimes integrated virus confers new properties on host
    • Specialized transduction-prophage brings bacterial DNA when leaves and puts in next bacterium it infects
  50. More
    • most common method of identifying viruses is culturing them on cell cultures
    • if cell detiriotes it's called CPE-cytopathic effects
    • viruses can be identified by theirCPE
    • also can be det. by looking for antibodies in patient's blood
    • certain viruses can agglutinate(clump)rbc, -HEMMAGLUTTINATION(HA)
    • if body has antibodies, it will bind to virus and prevent hemagluttiantion-hemm. inhibition (HAI)
    • bacteriophages can be found by inoculTION A LAWN -clear zones are plaques
  51. MORE
    • Viruses that dont kill host cell but aren't cleared out are called persistnt infection
    • some alter host cells and can cause cancer-oncogenic viruses-these cells hv been transformed
  52. Antibodies:
    • act to prevent viral repl. and agglutinate virus for phagocytisis
    • CD8/Tc cells and natural killer cells are effective at killing viruses but NOT antibodies
    • AZT used to combat aids-bas analog-looks liek normal nitr. base, but not so fools enzyme and stops replication of virus
    • Acyclovir used against genital herpes
    • reverse transcriptase inhibitors are drugs used to combat retroviruses like HIV that require reverse trans.
    • protease inhibitors another drug that
    • neuraminidase inhibitors are drugs that work on the spike of teh envelope of the virus
  53. Interferons:
    • 20 diff proteins made by virally infected cells
    • 3 classes alpha, beta, gamma
    • bind to neigh cells
    • act to block viral replication
    • interferon gamma IFN acts to mobilize natural killers
  54. Viral vaccines:
    • inactivated vaccines-killed virus used-not strongest immune response
    • attenuated virus-virus weakened then put in-stonger immune response
    • subunit virus-only genes from virus taken, put in object like yeast, (no actual virus used)-only viral antigen is injected into recipient-totally safe-Hep B -boosters may be used
  55. Viroids
    • smaller than viruses
    • tiny fragm. of naked Rna in plants
    • have no capsid
  56. Prions
    • Proteinaceous infectious particels-no nucleic acid present
    • formally called TSE-transmissible spongiform encephalopathy(mad cow disease)-due to it's effect on the brain
    • prions are misfolded forms of normal cellular protein
    • brought on by consumption of infected neural tissue
    • prioons don't reproduce but corrupt normal proteins
Card Set
Last Lecture Test 2011
Last Lecture test 2011