L33 Spirochetes Flashcards Preview

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Flashcards in L33 Spirochetes Deck (57)
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1
Q

What are the 3 shared features of spirochetes?

A
  1. Spiral morphology
  2. Flexible peptidoglycan cell wall
  3. 1+ axial fibrils (internal flagellum)
2
Q

What are the 3 major genera of spirochetes responsible for human disease?

A
  1. Treponema
  2. Borrelia
  3. Leptospira
3
Q

Borrelia is a larger spirochete that is spread from a mammalian reservoir to humans by ___, resulting in ___ or ___.

A

Tick/louse vectors; relapsing fever or Lyme disease

4
Q

What are the two major types of Borrelia species and what diseases do they cause, respectively?

A

Borrelia burgdorferi (Lyme) and Borrelia recurrentis (epidemic relapsing fever)

5
Q

What is the structure of Treponema pallidum?

A
  1. Thin, tightly coiled
  2. No LPS
  3. Poor growth in culture (microaerophilic; need rabbit epithelial cells; sensitive to drying and heat)
6
Q

Describe the epidemiology of Treponema pallidum (where is it found, how common is it, etc.).

A
  1. Worldwide
  2. 3rd most common STI in the U.S.
  3. Increase in prevalence
  4. Found only in humans
7
Q

How is Treponema pallidum transmitted?

A
  1. Direct sexual contact with infective primary or secondary mucosal lesion
  2. Congenital
  3. Transfusion (rare)
8
Q

True or false - Treponema pallidum cannot be sexually spread 4+ years after acquiring the infection.

A

True

9
Q

What is the major disease caused by Treponema pallidum?

A

Syphilis

10
Q

What are the 4 phases of syphilis?

A

Primary, secondary, latent, tertiary

11
Q

Describe the clinical symptoms of primary syphilis.

A
  1. Painless ulcer (chancre) at inoculation site - has smooth margins and a crusted base
  2. Painless regional lymphadenopathy (firm, local)
12
Q

Describe the clinical symptoms of secondary syphilis.

A
  1. Flu-like syndrome with fever
  2. Diffuse lymphadenopathy
  3. Generalized mucocutaneous rash including palms and soles
  4. Condylomata lata
  5. Hepatitis, aseptic meningitis, periostitis, nephritis
13
Q

Describe the clinical symptoms of latent syphilis.

A

Asymptomatic

14
Q

Describe the clinical symptoms of tertiary syphilis.

A
  1. Granulomatous lesions (gummas)
  2. Neurosyphilis
  3. Cardiovascular syphilis
15
Q

What are the lengths of the 4 phases of syphilis?

A

Primary: 10-90 days post-infection
Secondary: 2-10 weeks after chancres/peaks 3-4 months after infection
Latent: several to 25 years
Tertiary: 5-10 years since infection

16
Q

What are the 4 types of neurosyphilis and when does each type occur?

A
  1. Asymptomatic (secondary phase)
  2. Meningovascular (secondary phase)
  3. General paresis (tertiary phase)
  4. Tabes dorsalis (tertiary phase)
17
Q

What is the pathogenesis and symptoms in asymptomatic neurosyphilis?

A

Pathogenesis: CSF pleocytosis and elevated proteins

Symptoms: none

18
Q

What is the pathogenesis and symptoms in meningovascular neurosyphilis?

A

Path: menigitis, vasculitis

Symptoms: headache, stiff neck, fever, cranial neuropathy, stroke

19
Q

What is the pathogenesis and symptoms in general paresis neurosyphilis?

A

Path: chronic meningoencephalitis leading to brain atrophy

Symptoms: dementia, aphasia, muscle weakness, hallucinations

20
Q

What is the pathogenesis and symptoms in tabes dorsalis neurosyphilis?

A

Path: SC posterior and dorsal roots demyelinate

Symptoms: ataxia, loss of pain and temperature sensation

21
Q

Describe the progression and long-term effects of congenital syphilis.

A

Moves from asymptomatic to rhinitis, a widespread rash, and hepatomegaly

Long term effects: bone and teeth abnormalities, facial abnormalities, blindness, deafness, cardiovascular disease

22
Q

How is infection with Treponema pallidum diagnosed?

A
  1. Darkfield microscopy, direct fluorescent Ab, PCR (not preferred)
  2. Serology (preferred)
23
Q

Describe serologic diagnosis of Treponema pallidum.

A
  1. Non-treponemal tests: use reaginic Ab (IgG and IgM); often falsely positive
  2. Treponemal tests
24
Q

What are the reaginic Ab of non-treponemal tests binding to?

A

Bovine cardiolipin

25
Q

What are the 2 types of non-treponemal tests?

A
  1. VDRL

2. RPR

26
Q

True or false - treponemal tests remain positive for life.

A

True

27
Q

What are the three types of treponemal tests?

A
  1. Fluorescent treponemal Ab absorption (FTA-Abs)
  2. T. pallidum particle agglutination (TP-PA; TP-HA)
  3. T. palldium enzyme immunosassay (EIA)
28
Q

Describe the serologic reactivity in syphilis over the course of the disease.

A

IgM is positive in the majority of patients between the primary and secondary phases. Treponemal tests are positive in the majority of patients in the middle of the secondary phase. They remain as such. Non-treponemal tests are similar, but decrease during the latent phase (untreated less than treated).

29
Q

How is syphilis treated?

A
  1. Primary/early secondary: benzathine pencillin G (1 injection)
  2. Congenital, latent, tertiary: benzathine penicillin G (3 injections per week)
  3. Neurosyphilis: IV penicillin G

Alternative: doxycycline

30
Q

What is a possible reaction to antimicrobial treatment of Treponema palldium and Leptospirosis?

A

Jarsich-Herxheimer reaction

31
Q

Describe the structure of Borrelia burgdorferi.

A
  1. Not Gram + or -
  2. Larger than other spirochetes
  3. Stain with Giemsa or Wright
  4. Difficult to grow
32
Q

Describe the epidemiology of Borrelia burgdorferi (where is it found, how common is it, etc.).

A
  1. Leading vector-borne disease in the United States
  2. Animal reservoir: white-tailed deer, white-footed mouse
  3. Spread by hard ticks (primarily Ixodes scapularis)
33
Q

Where are the vast majority (95%) of cases of disease caused by Borrelia burgdorferi found?

A

Northeast and Mid-Atlantic US (primarily); also the Upper Midwest

34
Q

What is the major clinical manifestation of Borrelia burgdorferi?

A

Lyme disease

35
Q

What are the three stages of Lyme disease?

A
  1. Early
  2. Early disseminated
  3. Late
36
Q

What are the symptoms of early stage Lyme disease and what is its timeframe?

A

Erythema migrans (expanding erythematous target-shaped lesions at the site of the bite) + flu-like symptoms; 3-30 days post-bte

37
Q

What are the symptoms of early disseminated Lyme disease?

A

Flu-like symptoms, arthritis and arthralgia (60% of patients), erythematous skin lesion, cardiac dysfunction (conduction block), neurologic symptoms (facial nerve paralysis and other cranial nerve neuropathies, radiculopathy, meningitis, encephalomyelitis)

38
Q

What are the symptoms of late stage Lyme disease?

A

Recurrent arthritis in large joints and acrodermatitis chronica atrophicans (European only)

39
Q

What is a post-Lyme disease sequelae?

A

Post-Lyme Disease Syndrome (fatigue, cognitive defects, athralgias, myalgias, etc.)

40
Q

How is Lyme Disease diagnosed?

A
  1. Initial screening immunofluorescence assay (high rate of false positives, if positive, move on to #2)
  2. Western Blot (specific IgG, and IgM if <4 months from exposure)
41
Q

What are the neurologic symptoms used to diagnose Lyme Disease?

A
  1. Lymphocytic pleocytosis and increased protein in the CSF
  2. CSF seroogy
  3. CSF PCR
42
Q

How is Lyme Disease treated?

A

Early: doxycycline, amoxicillin, cefuroxime
Late: as above, but oral doses; exception: CNS Lyme disease - use ceftriaxone via IV

43
Q

Describe the structure of Borrelia recurrentis.

A
  1. Not Gram + or -
  2. Larger than other spirochetes
  3. Stain with Giemsa or Wright
  4. Difficult to grow
  5. Seen in blood smear with light microscopy
44
Q

What is the primary clinical manifestation of Borrelia recurrentis?

A

Relapsing fever (louse-borne)

45
Q

Compare the two types of relapsing fever.

A

Louse-borne: Caused by Borrelia recurrentis, human reservoir, transmited via crushed lice, found in areas with unsanitary conditions as well as Central/East Africa, epidemic, high mortality, one recurrence

Tick-borne: Caused by other Borrelia, rodent reservoir, transmitted via a tick bite, found worldwide, endemic, up to ten recurrences

46
Q

Describe the symptoms of relapsing fever.

A

Abrupt onset fever, chills, myaligas, headache, bactermic phase, splenomegaly, hepatomegaly; resolves in 3-7 days and recurs after 1 week (less severe)

47
Q

How is relapsing fever diagnosed?

A
  1. Giemsa/Wright blood smear

2. NOT serology

48
Q

Describe the pathogenicity of relapsing fever.

A

Borrelia species vary their antigens, leading to immune evasion and relapse

49
Q

What is the treatment for relapsing fever?

A

Tetracycline

Alternative: penicillins

50
Q

Describe the structure of Leptospiros.

A
  1. Thin, coiled spirochete with a hook
  2. Difficult to cutlure (need vitamins, fatty acids, salts)
  3. Obligate aerobes
  4. Can be seen with darkfield microscopy
51
Q

Describe the pathogenesis of infection with Leptospiros.

A

Zoonotic infection; humans encounter infected animal urine, which penetrates intact mucous membrane and skin through cuts. It spreads via the blood and damages the endothelium, leading to meningitis, hepatitis, renal dysfunction, hemorrhage, and myocarditis.

52
Q

Describe the epidemiology of Leptospiros (where is it found, how common is it, etc.).

A
  1. Worldwide
  2. 100-200 U.S. infections/year
  3. Animal hosts: dogs, pigs, cattle, horses
53
Q

How is Leptospiros transmitted?

A

Contact with urine of infected animals (contaminated food, water, soil, etc.); seen often from recreational exposure to contaminated water or occupationally

54
Q

Describe the clinical manifestation of Leptospiros.

A
  1. Stage 1 (bacteremia): fever, chills, headache, myalgias, conjunctival suffusion, abdominal pain
  2. Stage 2 (immune): aspetic meningitis, general illness with myalgias, headache, uvetitis, and rash
  3. Severe (blend): vascular collapse, thrombocytopenia, hepatitis, kidney problems, hemorrhage
55
Q

What is Weil’s disease?

A

Jaundice with hepatitis and no hepatic necrosis

56
Q

How is infection with Leptospiros diagnosed?

A
  1. Culture (blood and CSF early, urine late)
  2. Serology - microscopy agglutination test after the first week
  3. PCR
57
Q

How is infection with Leptospiros treated?

A

IV penicillin or doxycycline

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