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Flashcards in Spirochetes Deck (58):
0

How do the spirochetes multiply in general?

By transverse fission

1

Are the spirochetes motile in general?

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

2

Do spirochetes have exotoxins?

No.

3

Are spirochetes capable of being cultured on artificial media?

No. Except Leptospira.

4

Where is T.pallidum found?

Humans

5

How is T.pallidum transmitted?

Sexually

6

What is the morphology of T.pallidum?

Thick rigid spirals.

7

What is the metabolism of T.pallidum?

Microaerophilic and highly sensitive to elevated temperatures.

8

Is T.pallidum motile?

Yes.

9

What happens in the primary stage of syphilis?

Painless chancre (skin ulcer).

10

What happens in the secondary stage of syphilis?

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.

11

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

25%

12

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

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

13

What is the Jarisch-Herxheimer reaction?

Acute worsening of symptoms after antibiotics are started.

14

How do we diagnose syphilis?

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

15

Why all pregnant women should be screened with VDRL?

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

16

Where is T.pallidum endemicum found?

Desert zones of Africa and the Middle East.

17

How is T.pallidum endemicum transmitted?

Sharing of drinking and eating utensils.

18

What is the morphology of T.pallidum endemicum?

Indistinguishable from T.pallidum.

19

Is T.pallidum endemicum motile?

Yes

20

What can T.pallidum endemicum cause?

Bejel

21

What happens in Bejel?

1. Primary and secondary lesions occur in the oral mucosa.
2. Tertiary lesions - gummas of skin and bone.

22

How do we diagnose T.pallidum endemicum infection?

VDRL and FTA-ABS are positive.

23

Where is T.pertenue found?

Moist tropical regions.

24

How is T.pertenue transmitted?

Person-to-person contact or via flies.

25

What is the morphology of T.pertenue?

Indistinguishable from T.pallidum.

26

Is T.pertenue motile?

Yes

27

What can T.pertenue cause?

Yaws

28

What happens in yaws?

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

How do we diagnose T.pertenue?

VDRL and FTA-ABS positive.

30

Where is T.carateum found?

Latin America

31

How is T.carateum transmitted?

Person to person contact.

32

What is the morphology of T.carateum?

Indistinguishable from T.pallidum.

33

Is T.carateum motile?

Yes.

34

What can T.carateum cause?

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

35

How do we diagnose T.carateum?

VDRL and FTA-ABS positive.

36

Where is Borrelia burgdorferi found?

1. White footed mouse
2. White tailed deer

37

How is Borrelia Burgdorferi transmitted?

Vectors = Ixodes ticks.

38

What is the metabolism of B.burgdorferi?

Microaerophilic.

39

What can B.burgdorferi cause?

Lyme disease

40

What happens at the early stage of Lyme?

Erythema chronicum migrans

41

What happens at the early disseminated stage of Lyme?

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

What happens at the late stage of Lyme?

1. Chronic arthritis
2. Encephalopathy

43

How do we diagnose B.burgdorferi?

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

44

Where are the 18 other species of Borrelia found?

Wild rodents in remote indisturbed areas in the western US.

45

What is the virulence of other Borrelia species?

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

46

What can Borrelia species cause?

Relapsing fever

47

What happens in relapsing fever?

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

48

How do we diagnose Borrelia species?

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

How many serogroups and serovars has Leptospira interrogans?

23 serogroups and 250 serovars.

50

Where is L.interrograns found?

Zoonotic - dogs, cats, livestock, wild animals.

51

How is L.interrogans transmitted?

Direct contact with infected urine or animal tissue.

52

What is the metabolism of L.interrogans?

Aerobic

53

What is the morphology of L.interrogans?

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

What happens during the first phase of leptospiremic infection?

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

55

What happens during the second phase of leptospiremic infection?

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

56

What happens in Weil's disease?

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

57

How do we diagnose L.interrogans?

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