Yersinia, Francisella, Brucella, And Pasteurella Flashcards Preview

Microbiology > Yersinia, Francisella, Brucella, And Pasteurella > Flashcards

Flashcards in Yersinia, Francisella, Brucella, And Pasteurella Deck (43):
0

Where is Y.pestis found?

1. Wild rodents
2. City rats
3. Squirrels and prairie dogs in the SW U.S.

1

How is Y.pestis transmitted?

1. Flea bite
2. Contact with infected animal tissue
3. Inhaled aerosolized organisms - human to human transmission occurs during epidemics.

2

What is the metabolism of Y.pestis?

1. Facultative anaerobe
2. Virulence factors are temperature sensitive: only expressed at 37C (inside the macrophages).
3. Virulence is plasmid mediated.

3

What is the virulence of Y.pestis?

1. Fraction 1 (F1): this capsular antigen is antiphagocytic.
2. V and W proteins
3. Non motile
4. Requires Ca at 37C.

4

What are the toxins of Y.pestis?

1. Pesticin - kills other bacteria including E.coli.
2. Intracellular murine toxin - lethal to mice.

5

What can Y.pestis cause?

1. Bubonic plague
2. Sepsis
3. Pneumonic plague

6

What happens in bubonic plague?

1. Regional lymph nodes (groin) swell, become red, hot, and tender.
2. High fever
3. Conjunctivitis

7

What happens in pneumonic plague?

During epidemics, pneumonia occurs, as bacteria are spread from person to person by aerosolized respiratory secretions.
100% fatal if untreated.

8

How can we diagnose Y.pestis?

1. Gram (-) rods with bipolar staining.
2. Blood culture
3. Culture of bubo aspirate
4. Serology
5. Rapid diagnostic test: antibody against F1 (capsular antigen).

9

What is useful to keep in mind about Y.pestis?

1. Facultative intracellular parasite
2. Can accept plasmids from E.coli, and shares many antigens with enteric bacteria.
3. Subcutaneous hemorrhage results in a blackish skin discoloration. (Black Death).

10

Where is Y.enterocolitica found?

Wild and domestic animals.

11

How is Y.enterocolitica transmitted?

Via unpasteurized milk.

12

What is the metabolism of Y.enterocolitica?

1. Facultative anaerobe
2. Temperature sensitive virulence factors - only at 37C expressed

13

What is the virulence of Y.enterocolitica?

1. Invasive
2. V & W proteins
3. Motile at 25C

14

What are the toxins of Y.enterocolitica?

Enterotoxin (like ST toxin of E.coli): increase cGMP levels.

15

What can Y.enterocolitica cause?

1. Enterocolitis
2. Arthritis
3. Rash

16

How can we diagnose Y.enterocolitica?

Cold enrichment of stool with saline selects for Yersinia.

17

What is usefule to remember about Y.enterocolitica?

1. Facultative intracellular parasite
2. Bipolar staining

18

Where is F.tularensis found?

1. Rabbits and squirrels
2. Ticks can serve as a reservoir

19

How is F.tularensis transmitted?

1. Bite of tick, deerfly or infected animals.
2. Direct contact with infected animal tissue (usually rabbit)
3. Inhaled aerosolized organisms
4. Ingestion of contaminated meat or water
5. Easily transmitted to lab personnel.

20

What is the metabolism of F.tularensis?

1. Obligate aerobe
2. Requires cysteine

21

What is the virulence of F.tularensis?

1. Capsule: antiphagocytic
2. Non-motile

22

What are the main forms of tularemia?

1. Ulceroglandular
2. Pneumonia
3. Oculoglandular
4. Typhoidal

23

How can we diagnose F.tularensis?

1. Culture, though very dangerous due to high infectivity. Requires cysteine to blood agar media.
2. Skin test
3. Measure rise in IgG antibody titer (IgM is NOT very good).

24

What is useful to remember about F.tularensis?

Facultative intracellular parasite.

25

What are the 4 main Brucella species?

1. Brucella melitensis
2. Brucella abortus
3. Brucella suis
4. Brucella canis

26

Where is B.melitensis found?

Goats

27

Where is B.abortus found?

Cattle

28

Where is B.suis found?

Pigs

29

Where is B.canis found?

Dogs

30

How is Brucella transmitted?

1. Direct contact with contaminated live-stock or aborted placentas.
2. Ingestion of infected milk products.
3. Aerolization in laboratory or possibly due to bioterrorism

31

What is the metabolism of Brucella?

Obligate aerobe

32

What is the virulence of Brucella?

1. Capsule
2. Non motile
3. Tropism for erythritol, a sugar found in animal placentas

33

What happens in brucellosis?

1. Ubdulating fever - peaks in the evening, returns back to normal by morning.
2. Weakness
3. Loss of appetite

34

How can we diagnose Brucella?

1. Culture of blood, bone marrow (best), liver, or lymph nodes.
2. Serology
3. Skin test: indicates only exposure

35

What is useful to remember about Brucella?

Facultative intracellular parasite.

36

Where is Pasteurella multocida found?

Part of the normal flora of domestic and wild animals.

37

How is Pasteurella multocida transmitted?

Bite from dog or cat.

38

What is the metabolism of Pasteurella multocida?

Facultative anaerobe

39

What is the virulence of Pasteurella multocida?

1. Capsule
2. Non motile

40

What can Pasteurella multocida cause?

Wound infections that may progress to infection of nearby bones and joints.

41

How do we diagnose Pasteurella multocida?

Culture specimen on standard laboratory media.

42

What is useful to remember about Pasteurella multocida?

NOT a facultative intracellular parasite.