Listeria - Exam 2 Flashcards
Listeria is catalase ________.
Positive
True/False. Listeria is a faculative anaerobe.
True
True/False. Listeria is an extracellular organism.
FALSE! It is falculative intracellular pathogen!
How can you distinguish L. monocytogenes from other species of Listeria?
CAMP test with S. aureus
How can you distinguish L. invanovii from other species of Listeria?
CAMP test with R. equi
Which species is most frequently affected by Listeria spp?
RUMINANTS!
What are the general affects of Listeria on animal species?
Septicemia (multifocal to diffuse necrosis in the liver and spleen)
Encephalitis
Abortion
What protein gives Listeria the ability to disseminate without having to move to the extracellular environment?
ActA
(virulence factor of listeria that hijacks actin inside host cell and allows bacteria to move)
What is the main virulence factor of Listeria and what is it’s function?
Listeriolysin O (LLO)
Pore-forming cytolisin that releases the bacteria from the phagosome into the cytosol
What is the most natural reservior of Listeria?
Decomposing plant matter
How is Listeria transmitted?
Soil contamination (fecal-oral enrichment)
Ingestion of contaminated feed (ruminants)
Nasal mucosa and conjunctivae
Why are very young and very old animals infected more easily with Listeria?
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.
Which types of cells do Listeria typically enter and survive in?
Epithelial cells
M-cells
Phagocytic cells
Hepatocytes
Endothelial cells
What is the most common manisfestation of Listeria in Ruminants?
Encephalitis (circling disease)
Which type of exotic species is espeically susceptible to listerial septicemia?
Chinchillas
What is the most common manifestation of Listeria in humans?
Meningitis
Which seasons can animals be more susceptible to Listeria?
Winter and spring
What is the most classic source of infection of Listeria in ruminants?
Contaminated silages
Listeria produces ____-hemolysis and grows best under which conditions?
Narrow zone of beta-hemolysis
Grows best under reduced O2 and increased CO2
