Listeria - Exam 2 Flashcards

1
Q

Listeria is catalase ________.

A

Positive

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2
Q

True/False. Listeria is a faculative anaerobe.

A

True

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3
Q

True/False. Listeria is an extracellular organism.

A

FALSE! It is falculative intracellular pathogen!

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4
Q

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

A

CAMP test with S. aureus

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5
Q

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

A

CAMP test with R. equi

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6
Q

Which species is most frequently affected by Listeria spp?

A

RUMINANTS!

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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

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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)

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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

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10
Q

What is the most natural reservior of Listeria?

A

Decomposing plant matter

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11
Q

How is Listeria transmitted?

A

Soil contamination (fecal-oral enrichment)

Ingestion of contaminated feed (ruminants)

Nasal mucosa and conjunctivae

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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.

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13
Q

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

A

Epithelial cells

M-cells

Phagocytic cells

Hepatocytes

Endothelial cells

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14
Q

What is the most common manisfestation of Listeria in Ruminants?

A

Encephalitis (circling disease)

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15
Q

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

A

Chinchillas

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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