Yersinia, Francisella, Brucella, And Pasteurella

Question 0

How is Y.pestis transmitted?

Answer 0

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

Question 1

Where is Y.pestis found?

Answer 1

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

Question 2

What is the metabolism of Y.pestis?

Answer 2

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

Question 3

What is the virulence of Y.pestis?

Answer 3

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

Question 4

What are the toxins of Y.pestis?

Answer 4

1. Pesticin - kills other bacteria including E.coli.

2. Intracellular murine toxin - lethal to mice.

Question 5

What can Y.pestis cause?

Answer 5

1. Bubonic plague
2. Sepsis
3. Pneumonic plague

Question 6

What happens in bubonic plague?

Answer 6

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

Question 7

What happens in pneumonic plague?

Answer 7

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

Question 8

How can we diagnose Y.pestis?

Answer 8

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).

Question 9

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

Answer 9

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).

Question 10

Where is Y.enterocolitica found?

Answer 10

Wild and domestic animals.

Question 11

How is Y.enterocolitica transmitted?

Answer 11

Via unpasteurized milk.

Question 12

What is the metabolism of Y.enterocolitica?

Answer 12

1. Facultative anaerobe

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

Question 13

What is the virulence of Y.enterocolitica?

Answer 13

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

Question 14

What are the toxins of Y.enterocolitica?

Answer 14

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

Question 15

What can Y.enterocolitica cause?

Answer 15

1. Enterocolitis
2. Arthritis
3. Rash

Question 16

How can we diagnose Y.enterocolitica?

Answer 16

Cold enrichment of stool with saline selects for Yersinia.

Question 17

What is usefule to remember about Y.enterocolitica?

Answer 17

1. Facultative intracellular parasite

2. Bipolar staining

Question 18

Where is F.tularensis found?

Answer 18

1. Rabbits and squirrels

2. Ticks can serve as a reservoir

Question 19

How is F.tularensis transmitted?

Answer 19

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.

Question 20

What is the metabolism of F.tularensis?

Answer 20

1. Obligate aerobe

2. Requires cysteine

Question 21

What is the virulence of F.tularensis?

Answer 21

1. Capsule: antiphagocytic

2. Non-motile

Question 22

What are the main forms of tularemia?

Answer 22

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

Question 23

How can we diagnose F.tularensis?

Answer 23

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).

Question 24

What is useful to remember about F.tularensis?

Answer 24

Facultative intracellular parasite.

Question 25

What are the 4 main Brucella species?

Answer 25

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

Question 26

Where is B.melitensis found?

Answer 26

Goats

Question 27

Where is B.abortus found?

Answer 27

Cattle

Question 28

Where is B.suis found?

Answer 28

Pigs

Question 29

Where is B.canis found?

Answer 29

Dogs

Question 30

How is Brucella transmitted?

Answer 30

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

Question 31

What is the metabolism of Brucella?

Answer 31

Obligate aerobe

Question 32

What is the virulence of Brucella?

Answer 32

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

Question 33

What happens in brucellosis?

Answer 33

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

Question 34

How can we diagnose Brucella?

Answer 34

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

Question 35

What is useful to remember about Brucella?

Answer 35

Facultative intracellular parasite.

Question 36

Where is Pasteurella multocida found?

Answer 36

Part of the normal flora of domestic and wild animals.

Question 37

How is Pasteurella multocida transmitted?

Answer 37

Bite from dog or cat.

Question 38

What is the metabolism of Pasteurella multocida?

Answer 38

Facultative anaerobe

Question 39

What is the virulence of Pasteurella multocida?

Answer 39

1. Capsule | 2. Non motile

Question 40

What can Pasteurella multocida cause?

Answer 40

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

Question 41

How do we diagnose Pasteurella multocida?

Answer 41

Culture specimen on standard laboratory media.

Question 42

What is useful to remember about Pasteurella multocida?

Answer 42

NOT a facultative intracellular parasite.