Listeria - Exam 2 Flashcards Preview

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Flashcards in Listeria - Exam 2 Deck (19)
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1
Q

Listeria is catalase ________.

A

Positive

2
Q

True/False. Listeria is a faculative anaerobe.

A

True

3
Q

True/False. Listeria is an extracellular organism.

A

FALSE! It is falculative intracellular pathogen!

4
Q

How can you distinguish L. monocytogenes from other species of Listeria?

A

CAMP test with S. aureus

5
Q

How can you distinguish L. invanovii from other species of Listeria?

A

CAMP test with R. equi

6
Q

Which species is most frequently affected by Listeria spp?

A

RUMINANTS!

7
Q

What are the general affects of Listeria on animal species?

A

Septicemia (multifocal to diffuse necrosis in the liver and spleen)

Encephalitis

Abortion

8
Q

What protein gives Listeria the ability to disseminate without having to move to the extracellular environment?

A

ActA

(virulence factor of listeria that hijacks actin inside host cell and allows bacteria to move)

9
Q

What is the main virulence factor of Listeria and what is it’s function?

A

Listeriolysin O (LLO)

Pore-forming cytolisin that releases the bacteria from the phagosome into the cytosol

10
Q

What is the most natural reservior of Listeria?

A

Decomposing plant matter

11
Q

How is Listeria transmitted?

A

Soil contamination (fecal-oral enrichment)

Ingestion of contaminated feed (ruminants)

Nasal mucosa and conjunctivae

12
Q

Why are very young and very old animals infected more easily with Listeria?

A

When Listeria is orally ingested, most is killed by gastric acids. Young and old animals do not have a totally functioning stomach and cannot kill off a high number of bacteria initially.

13
Q

Which types of cells do Listeria typically enter and survive in?

A

Epithelial cells

M-cells

Phagocytic cells

Hepatocytes

Endothelial cells

14
Q

What is the most common manisfestation of Listeria in Ruminants?

A

Encephalitis (circling disease)

15
Q

Which type of exotic species is espeically susceptible to listerial septicemia?

A

Chinchillas

16
Q

What is the most common manifestation of Listeria in humans?

A

Meningitis

17
Q

Which seasons can animals be more susceptible to Listeria?

A

Winter and spring

18
Q

What is the most classic source of infection of Listeria in ruminants?

A

Contaminated silages

19
Q

Listeria produces ____-hemolysis and grows best under which conditions?

A

Narrow zone of beta-hemolysis

Grows best under reduced O2 and increased CO2