Spirochetes Flashcards

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0
Q

Are the spirochetes motile in general?

A

Yes.
6 axial filaments wind around the organism between the peptidoglycan layer and the outer cell membrane.
Contraction of axial filaments conveys spinning motion.

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1
Q

How do the spirochetes multiply in general?

A

By transverse fission

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2
Q

Do spirochetes have exotoxins?

A

No.

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3
Q

Are spirochetes capable of being cultured on artificial media?

A

No. Except Leptospira.

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4
Q

Where is T.pallidum found?

A

Humans

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5
Q

How is T.pallidum transmitted?

A

Sexually

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6
Q

What is the morphology of T.pallidum?

A

Thick rigid spirals.

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7
Q

What is the metabolism of T.pallidum?

A

Microaerophilic and highly sensitive to elevated temperatures.

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8
Q

Is T.pallidum motile?

A

Yes.

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9
Q

What happens in the primary stage of syphilis?

A

Painless chancre (skin ulcer).

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10
Q

What happens in the secondary stage of syphilis?

A
  1. Rash on palms and soles
  2. Condyloma latum: painless, wartlike lesion which occurs in warm, moist places (vulva, scrotum).
  3. CNS, eyes, bones, kidneys and/or joints can be involved.
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11
Q

What percentage of patients in the latent phase can relapse into the secondary phase of syphilis?

A

25%

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12
Q

What happens in the tertiary phase of syphilis (33%)?

A
  1. Gummas of the skin and bone.
  2. Cardiovascular syphilis.
  3. Neurosyphilis: may get the Argyll-Robertson pupil.
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13
Q

What is the Jarisch-Herxheimer reaction?

A

Acute worsening of symptoms after antibiotics are started.

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14
Q

How do we diagnose syphilis?

A
  1. Cutaneous lesions examined by dark-field microscopy, immunofluorescence, ELISA, or silver stain.
  2. Non specific treponemal test
    : VDRL; BPR.
  3. Specific treponemal tests: FTA-ABS, MHA-TP.
  4. PCR
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15
Q

Why all pregnant women should be screened with VDRL?

A

Because antibiotic treatment prior to 4 months of gestation prevents congenital syphilis.

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16
Q

Where is T.pallidum endemicum found?

A

Desert zones of Africa and the Middle East.

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17
Q

How is T.pallidum endemicum transmitted?

A

Sharing of drinking and eating utensils.

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18
Q

What is the morphology of T.pallidum endemicum?

A

Indistinguishable from T.pallidum.

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19
Q

Is T.pallidum endemicum motile?

A

Yes

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20
Q

What can T.pallidum endemicum cause?

A

Bejel

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21
Q

What happens in Bejel?

A
  1. Primary and secondary lesions occur in the oral mucosa.

2. Tertiary lesions - gummas of skin and bone.

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22
Q

How do we diagnose T.pallidum endemicum infection?

A

VDRL and FTA-ABS are positive.

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23
Q

Where is T.pertenue found?

A

Moist tropical regions.

24
Q

How is T.pertenue transmitted?

A

Person-to-person contact or via flies.

25
Q

What is the morphology of T.pertenue?

A

Indistinguishable from T.pallidum.

26
Q

Is T.pertenue motile?

A

Yes

27
Q

What can T.pertenue cause?

A

Yaws

28
Q

What happens in yaws?

A
  1. Primary and secondary lesions –> ulcerative skin lesions near initial site of infection - often looks like Condyloma lata.
  2. Tertiary lesions –> gummas of skin and bone (resulting in severe facial disfigurement).
29
Q

How do we diagnose T.pertenue?

A

VDRL and FTA-ABS positive.

30
Q

Where is T.carateum found?

A

Latin America

31
Q

How is T.carateum transmitted?

A

Person to person contact.

32
Q

What is the morphology of T.carateum?

A

Indistinguishable from T.pallidum.

33
Q

Is T.carateum motile?

A

Yes.

34
Q

What can T.carateum cause?

A

Pinta - flat red or blue lesions which do not ulcerate.

35
Q

How do we diagnose T.carateum?

A

VDRL and FTA-ABS positive.

36
Q

Where is Borrelia burgdorferi found?

A
  1. White footed mouse

2. White tailed deer

37
Q

How is Borrelia Burgdorferi transmitted?

A

Vectors = Ixodes ticks.

38
Q

What is the metabolism of B.burgdorferi?

A

Microaerophilic.

39
Q

What can B.burgdorferi cause?

A

Lyme disease

40
Q

What happens at the early stage of Lyme?

A

Erythema chronicum migrans

41
Q

What happens at the early disseminated stage of Lyme?

A
  1. Multiple smaller erythemas.
  2. Neurologic –> aseptic meningitis, cranial nerve palsies (Bell’s palsy), peripheral neuropathy.
  3. Cardiac –> Transient heart block or myocarditis.
  4. Brief attacks of arthritis of large joints.
42
Q

What happens at the late stage of Lyme?

A
  1. Chronic arthritis

2. Encephalopathy

43
Q

How do we diagnose B.burgdorferi?

A
  1. Elevated levels of antibodies against B.burgdorferi can be detected by ELISA.
  2. Western blot
44
Q

Where are the 18 other species of Borrelia found?

A

Wild rodents in remote indisturbed areas in the western US.

45
Q

What is the virulence of other Borrelia species?

A
  1. Antigenic variation - variable expression of outer membrane Vmp lipoproteins allows Borrelia to escape opsonization and phagocytosis.
  2. No toxins
46
Q

What can Borrelia species cause?

A

Relapsing fever

47
Q

What happens in relapsing fever?

A
  1. Recurring fever every 8 days.
  2. Fever breaks with drenching sweats.
  3. Rash and splenomegaly.
  4. Occasionally meningeal involvement.
48
Q

How do we diagnose Borrelia species?

A
  1. Blood cultures during febrile periods.
  2. Dark field examination of blood drawn during febrile periods.
  3. Wright’s or Giemsa- stained peripheral blood smear reveals organism 70% of the time.
  4. Serologic
49
Q

How many serogroups and serovars has Leptospira interrogans?

A

23 serogroups and 250 serovars.

50
Q

Where is L.interrograns found?

A

Zoonotic - dogs, cats, livestock, wild animals.

51
Q

How is L.interrogans transmitted?

A

Direct contact with infected urine or animal tissue.

52
Q

What is the metabolism of L.interrogans?

A

Aerobic

53
Q

What is the morphology of L.interrogans?

A
  1. Spiral shaped with hooks on both ends.
  2. Two axial flagella wrap around and run along the length of the organism under the outer membrane (periplasmic flagella).
54
Q

What happens during the first phase of leptospiremic infection?

A

Organisms in the blood and CSF causes high spiking temperatures, headache and severe muscle aches (thighs and lower back).

55
Q

What happens during the second phase of leptospiremic infection?

A

Correlates with the emerge of IgM and involves recurrence of the symptoms often with meningismus (neck pain).

56
Q

What happens in Weil’s disease?

A

Severe case of leptospirosis with renal failure, hepatitis (and jaundice), mental status changes, and hemorrhage in many organs.

57
Q

How do we diagnose L.interrogans?

A

1st wk: culture blood or CSF.
2nd wk to months: culture urine.
Also PCR and ELISA.