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Flashcards in Rickettsia and Related Microbes Deck (70)
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1

What is the general information about Rickettsia?

Gram negative rods, obligate intracellular bacteria

2

Can Rickettsia be cultured on agar media?

Nope

3


What are the 3 phyla of Rickettsia and related microbes?



Rickettsia (vector-borne), Ehrlichia (vector), Coxiella (non vector-borne)


4

In general, how is the diagnosis of a Rickettsia organism made?

Pt presentation and history (travel/exposure), confirm with serology

5

What drug are the Rickettsia and others responsive to?

Doxycycline

6

What is the classic presentation of Rickettsia?

Fever, Headache, Rash

7

Where do Rickettsia replicated? In which Cells? What does this cause?

In cytoplasm of endothelial and muscle cells of small blood vessels, hemorrhage and edema, dz is vasculitis leading to rash and headache

8

What is responsible for Rocky Mountain Spotted Fever?

R. Rickettsia

9

How is R. Rickettsia transmitted?

Various ticks (microbes replicate in salivary gland). So it is seasonal, when ticks are active

10

Where is the highest incidence of R. Rickettsia?

NC, SC, AR, MO, OK, TN (endemic in TN)

11

What are initial symptoms of R. Rickettsia?

FLS with severe headache followed by rash, also, significant muscle tenderness (calf)

12

Where is the rash of RMSF?

Spreads from ankles and wrists to soles, palms, and trunk

13

What happens when the rash of RMSF spreads?

Infection becomes systemic...septicemia... DIC

14

How is the Dx of RSMF made?

Initially made on presnetation and Hx, nonspecific Weil-Felix serologic test measures x-reactivity of Anti-rickettsial Ab's to Proteus OX strains; must confirm by comparison of acute and convalescent sera. Indirect fluorescent Ab assay now used mostly

15

How many people die of RSMF if untreated? What is Tx?

1 in 4; Doxy within first week; septicemia often mistreated with beta-lactams which doesnt work

16

How do you prevent RMSF?

Use DEET to avoid tick bites or remove tick within 4 hours of bite

17

What does R. prowazekii cause?

Epidemic typhus; dz associated with wars and poverty

18

Is R. Prowazekii a zoonosis?

nope

19

How is Epidemic Typhus transferred?

Human to human via body lice

20

Epidemic typhus is similar to RMSF, so how do you distinguish them?

It spreads from trunk to extremities instead of the other way around

21

What are the two bugs classified as Ehrlichia?

E. Chaffeensis (HME) and Anaplasma phagocytophilia (HGA)

22

How are HME and HGA transmitted?

Ticks, but not the same as RMSF geography

23

What cell does R. Chaffeensis replicate in?

Monocytes

24

What cell does A. phagocytophilia replicate in?

Granulocytes

25

Replicating microbes from inclusion bodies in monocytes/granulocytes from HMA/HGA are called what?

Morulae

26

What are the symptoms of HME/HGA?

generally more mild than RMSF; FLS's, and rash is less common

27

Do HMA/HGA bugs have a Weil-Felix reaction?

No

28

How is E. Chaffeensis transmitted?

Lone star deer tick

29

How is the diagnosis of E. Chaffeensis made?

Wright/Giemsa stain of blood smear shows morulae in monocytes and serology

30

How do you treat both E. Chaffeensis and A. Phagocytophilia?

Doxy

31

What is the nickname for the dz caused by A. Phago?

Rocky Mountain SpotLESS fever because rash is so rare

32

How is A. Phago transmitted?

Ixodes deer tick

33

How is Dx of A. Phago made?

Wright/Giemsa stain of blood smear shows morular in granulocytes + serology

34

What is the shape of Borrelia?

Spirochetes

35

How can spirochetes of Borrelia be seen?

Wright/Giemsa stain

36

What characteristic plays a role in relapsing fever of Borrelia?

Antigenic variation

37

What is the causative agent of Lyme Dz?

B. Burgdorferi

38

How is LD transmitted to humans?

Via ixodes deer tick nymph which is extremely small and hard to detect

39

How can one prevent LD?

Remove tick within 24 hours

40

True or False, LD is the most common tickborne dz in the US?

True

41

Where is LD endemic?

New England, Mid Atlantic states, Upper midwest, also in TN

42

What are the early LD symptoms?

FLS usually milder than RMSF, classic bulls eye rash at site of tick bite called erythema chronicum migrans (not always seen)

43

What are the secondary LD symptoms (disseminated)

Arthritis, facial palsy, peripheral neuropathy. Occurs weeks or months after initial infection

44

How is the Dx of LD made?

2 step serological testing: ELISA + Western Blot. PCR based NAATs now available

45

What is the Tx for early LD?

Doxy or Amoxicillin

46

What is the Tx for chronic Ld?

IV Cephalosporins for extended periods

47

What are the causative agents of Relapsing Fever?

B. Hermsii and B. Revurrentis

48

How is B. Hermsii transmitted?

Tick

49

How is B. Recurrentis transmitted?

Louse

50

Where is B Hermsii endemic?

HIgh, dry areas of Western US

51

Is B. recurrentis common or rare in the US?

Rare

52

What are the symptoms of Relapsing Fever?

Recurrent fever that is on one week, off two, rash uncommon

53

How can one see B. Hermsii or Recurrentis?

Wright/Giemsa stain of blood smear

54

What is needed to confirm Dx of relapsing fever?

Serology

55

What is the tx for relapsing fever?

Doxy

56

What is the causative agent of Leptospirosis?

Leptospira Interrogans

57

What are the L. Interrogans?

Spirochetes

58

How is L. Interrogans transmitted?

Through water contaminated with animal urine usually through a break in the skin

59

Does L. Interrogans cause skin lesions?

Lol, no

60

What can L. Interrogans cause?

FLS, Weil's Dz (jaundice + renal damage), meningitis

61

How is the Dx of interrogans made?

Serology

62

What is the Tx for Leptosporosis?

Penicillin

63

What has reduced the incidence of Leptosporosis in humans?

Vaccination of cattle and household pets

64

What dz does Bartonella henselae cause?

Cat Scratch Dz

65

What is the reservoir of B. Henselae?

Cats (but they're not affected)

66

What patient population is B. Heneselae seen in?

Children

67

What symptoms are seen with Cat Scratch Dz?

Swollen LN's near site of scratch, adults can also have FLS, can lead to severe disseminated Dz involving CNS in ICP's

68

How is the diagnosis of Cat Scratch Dz made?

Presentation and Hx of scratch or bite

69

What is the treatment for Cat Scratch? Tx for long lasting infections?

Most infections clear on their own in two weeks; Erythro for longer infections

70

What other bugs can cause skin lesions or swollen glands?

Anthrax (Eschar); Plague (Bubo in groin or axilla); Tularemia (Ulcer)