Micro Test 3: Arthropod Borne Bacteria

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Micro Test 3: Arthropod Borne Bacteria
2012-12-02 19:22:10
Arthropod Borne Bacteria

Arthropod Borne Bacteria
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  1. Borrelia
    Gram-N spirochetes
  2. Rickettsia, Ehrlichia, Orientia, Anaplasma, and Coxiella are all
    obligate intracellular parasites
  3. Name 5 obligate intracellular parasites
    Rickettsia, Ehrlichia, Orientia, Anaplasma, and Coxiella
  4. What organism causes Lyme disease?
    Borrelia burgdorferi (Gram-N spirochete)
  5. What organism causes Rocky Mountain Spotted Fever?
    Rickettsia rickettsii
  6. What two organisms are transmitted by body lice, and thus have a solely human reservoir?
    Borrelia recurrentis, R. prowazekki(epidemic typhus), R. quintana (trench fever)
  7. What drug/class works very well on these diseases?
    Doxycycline (tetracycline)
  8. Name 3 spirochete disease agents
    • Borrelia
    • Leptospira
    • Treponema
  9. Borrelia causes Lyme disease which is characterized by
    relapsing fevers
  10. Spirochetes:
    Not usually visible with conventional light microscopy
    • Anaerobic
    • Corkscrew motility
  11. Most common tickborne illness in N. America and Europe
    Lyme Disease, caused by Borrelia burgdorferi
  12. Borrelia burgdorferi:
    Difficul to grow in vitro
    Outer sheath?
    • Microaerophilic
    • Few proteins in outer sheath, most of those are lipoproteins which are potent activators of innate immunity via TLRs
    • Phase variation
  13. When is lyme disease most commonly diagnosed?  Which forms of tick are most commonly the transmitters of lyme disease? 
    Most commonly diagnosed in june/july (summer).  Nymph and larva are most likely to cause disease because they are smaller and thus harder to feel on you.  They must be on you 36-48 hours before you get lyme disease.
  14. Characteristic expanding (bulls-eye) rash at site of tick bite in 60-80% of patients is called _____ and is diagnostic of?
    Erythema migrans, Lyme disease
  15. Early Localized Lyme Disease presents with?
    Cure rate at this stage?
    • Erythema migrans
    • Flu-like symptoms- fever, headache, malaise, fatigue, myalgia, arthralgia, regional lymphadenopathy

    99% cure rate at this stage

    HOWEVER mostly misdiagnosed at this stage if there is no erythema migrans
  16. Disseminated multiple erythema migrans is characteristic of what lyme disease stage?
    Early Disseminated Lyme Disease

    Can present with Bell's palsy and arthritis in large joints
  17. Stages of Lyme Disease and characteristic symptoms:
    • 1)  Early Localized Lyme Disease:  Erythema migrans at site of tick bite, flu-like symptoms
    • 2)  Early Disseminated Lyme Disease:  Disseminated multiple erythema migrans, arthritis in large joints, Bell's palsy
    • 3)  Late Disseminated (Chronic) Lyme Disease:  Chronic arthritis w/ pain and swelling, neurologicl disorders (numbness, tingling, shooting pains), cognitive defects (short-term memory loss), sleep disturbances, fatigue
  18. In Late Disseminated Lyme Disease:  Are spirochetes found in affected tissue?  What is hypothesized?  Why?
    No spirochetes in affected tissue, autoimmune involvement is thought to be involved because it is associated with certain haplotypes.
  19. What is the only stage of Lyme disease that does NOT respond well to antibiotics?
    Late Disseminated (Chronic) Lyme Disease
  20. Lyme Arthritis occurs in what stage of Lyme Disease?  What joints does it primarily effect?
    • Late Disseminated (Chronic) Lyme Disease
    • Affects larger joints (knee or elbow), usually affects a SINGLE joint, bone/cartilage destructin are RARE
  21. Lyme Disease Tx:
    Erythema migrans/ facial palsies, mild cardiac disease
    Doxycycline, amoxicillin, or cefuroxime axetil
  22. Lyme Disease Tx:
    Neurologic disease /cardiac disease/ arthritis
    • Ceftriaxone IV
    • (or doxycycline, amoxicillin, or cefuroxime axetil for up to 1 month)
  23. Post-Tx Lyme Disease: (PTLDS)
    Occurs in what percent of patients?
    • 10% (last for months to years)
    • Arthralgias, myalgias, cognitive defects, sleep disturbances, fatigue
    • Possibly an autoimmune response
  24. Relapsing Fever caused by
    • Epidemic:  Borrelia recurrentis
    • Endeic:  B. hermsii, B. turicatae
  25. Relapsing Fever caused by Borrelia recurrentis (Epidemic) is transmitted by
    Body lice (via skin abrasions by hemolymph of crushed lice)

    More severe disease, only imported cases in USA
  26. Relapsing Fever caused by B. hermsii and B. turicatae (Endemic ) transmitted by
    • soft ticks
    • 30 cases/yr in USA
  27. Relapsing Fever:
    Epidemic --> B. recurrentis --> Lice (single relapse)
    Endemic --> B. hermsii, B. turicatae --> soft ticks (3-10 episodes)
  28. Spirochetes in blood that undergo antigenic variation are seen in
    Relapsing Fever
  29. Relapsing fever can cause
    • Flu-like symptoms
    • Hepatosplenomegaly, Jaundice
    • Spontaneous abortion, premature birth
  30. What stain do you use to stain spirochetes in Relapsing Fever?
  31. Tx for Relapsing Fever
    Doxycycline (tetracycline), Erythromycin (macrolide)- in pregnant women or children since can't use tetracycline

    If Neurologic involvement:  Ceftriaxone
  32. Monitor patients being treated for Relapsing Fever for ____
    Jarish-Herxheimer rxn (50%)
  33. Jarish-Herxheimer reaction can be seen in patients being treated for
    Relapsing Fever
  34. Rickettsia, Orientia, Coxiella, Ehrlichia, and Anaplasma:
    Aerobic or anaerobic?
  35. Of the obligate intracellular bacteria, which ones escape the endocytic vacuole?  Where do they infect?
    • They escape vacuole and ROVe the cell.
    • 1) Rickettsia- endothelial cells of small blood vessels
    • 2) Orientia- blood vessel epithelium, macrophages
    • 3) Vasicuitis/rash for Rickettsia and Orientia
  36. Of the obligate intracellular bacteria, which ones remain in the endocytic vacuole of the host cell (morulae)
    • Coxiella and Ehrlichia- monocytes and macrophages
    • Anaplasma- neutrophils
  37. Two forms of Rickettsioses
    Both are sensitive to _____
    • 1)  Spotted Fever Group
    • 2)  Typhus Group

    Sensitive to doxycycline
  38. Rickettsioses:  Spotted Fever Group
    Type of rash?
    Rocky Mountain Spotted fever caused by?
    • Ticks
    • Centripetal (spreads from extremities to trunk)
    • R. rickettsii
  39. Which type of Rickettsia infection causes spotted fever with eschar?
    R. parkeri
  40. 4 Types of Recketssia in Spotted Fever Group
    • R. rickettsii - Rocky Mountain Spotted Fever
    • R. parkeri - Spotted fever w/ eschar
    • R. akari - Rickettsialpox
    • R. coronii - Mediterranean Spotted Fever (MSF)
  41. 2 Types of Reckettsia in Typhus group
    • R. typhi (fleas)
    • R. prowazekii (lice)
  42. Types of Rash
    Spotted Fever Rickettsias:
    Typhus Rickettsias:
    • SFR:  Centripetal (extremities to trunk)
    • TR:  Centrifugal (trunk to extremities)
  43. Classic triad of RMSF
    • Fever
    • Headache
    • Rash (ankles/wrists --> palms, soles, trunk, face)
  44. Rickettsialpox causative agent?
    Found in?
    Presenting symptom.
    Treat with?
    • Rickettsia akari (transmitted by mouse bite)
    • Urban areas
    • Eschar forms at bite site
    • Treat with doxycycline, quinolones
  45. Eschar + mousebite =
    Ricketssialpox (Rickettsia akari)
  46. Causative agent of Endemic or Murine Typhus (NOT typhoid)
    Causesd by Rickettsia typhi
  47. Epidemic Typhus
    Transmission, causative agent.
    Louse borne, R. prowazekki
  48. Causative agent of Scrub Typhus
    Spread by?
    Found in?
    • Orientia tsutsugamushi
    • Chiggers
    • Asia, Western Pacific
    • Rash with eschars spreads from trunk to extremities, CNS complications
    • Doxycycline
  49. Ehrlichhia:
    Human Monocytic Erlichiosis (HME):  Morulae in cytoplasem of ______
    Human Granulocytic Anaplasmosis (HGE):  Morulae in cytoplasm of _____
    • Monocyte
    • Neutrophil

    Both are transmitted by hard ticks
  50. Two cell types of Coxiella burnetti
    • Small cell variant (SCV)- small like spore, can survive for months
    • Large cell variant (LCV)- found in body, can survive at low pH's (allows phagolysosome fusion)
  51. Q fever causative agent
    Most common in
    • Coxiella burnetti
    • Most prevalent in active men, 25-40 year
  52. Primary reservoir of Coxiella burnetti
    Cattle, sheep, goats
  53. 30 year old male sheep/goat farmer probably has
    Q fever (Coxiella burnetti)
  54. Disease that's almost exclusively in patients with heart disease or valve defects--> subacute endocarditis
    Chronic Q fever
  55. Disease that can cause spontaneous abortion or premature labor in pregnant women.
    Ab to Phase I and Phase II antigen (LPS)
    Chronic Q fever
  56. Category B-Bioterorrism Agen because it is highly infections an dcan be airborne
    Coxiella burnetii