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16 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Gram, catalase, shape, haemolysis |
Gram positive, catalase positive, rod, narrow area of beta haemolysis |
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Where is listeria monocytogenes found and what hosts can it infect |
Soil, (saprophyte) silage, dairy products, cheeses
Ruminants, cows |
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Where does listeria replicate |
Intracellular cytosol of epithelial cells and macrophages (and none professional phagocytes) |
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Why can listeria survive and replicate outside of a host |
It can survive cold temperatures, acidic environments, and high salt conc |
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How might listeria be transmitted |
Foods such as cheese. Fruit and veg. Soil contamination, water contamination, silage and faecal matter. Nosocomial infection in neonatal units through formites like aspirators |
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What are symptoms of listeria infection |
Listeriosis in immune compromised patients Fever, neurological signs, nausea, vomiting, In pregnant patients - spontaneous abortion, septicaemia, cervical/intrauterine infection |
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What are worst case scenarios of listeria infection |
Meningo encephalitis Neonatal sepsis or meningitis |
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How is listeria infection treated |
Aminopenicillin (+gentamicin in CNS infections) |
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How can listeria cause spontaneous abortion and prenatal meningitis |
It can cross the placental barrier and blood brain barrier |
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The invasive form of Listeria infection is known as listeriosis, what is non invasive infection called? |
Gastroenteritis |
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Name some virulence factors in listeria |
Listeriolysin O (LLO)
PLCb gene - makes phospholipidase C which breaks down phospholipid so listeria can escape from phagosome and replicate in cytosol
InL - internalins which promote adhesion and invasion of host cells
ActA - recruits acting filaments to form acting comet tail allowing for invasion of neighbouring cells |
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What does LLO do |
Creates pores in host cells membranes to disrupt ion balance and compromise internal processes in organelles like mitochondria. Calcium influx - cell death, inflammation, disruption of signal transduction Vacuole escape to cytoplasm Disruption of post translational modifications like simulation and immune response . |
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How does listeria enter host cells and invade neighbouring cells |
Adhesion to cell surface - InlA on listeria binds to e-cadherin on surface of epithelial cells in intestine
InlB binds to Met - disrupts host cells signalling, promotes uptake of listeria
Escape from Phagosome - PlCb gene and LLO, acidifies vacuole and disrupts it
Replicate in cytosol
ActA - and InlC Acting based motility - ActA - formation of actin comet tail, invasion of neighbouring cell through formation of protrusion (InlC) and cell to cell spread |
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What is the immune response to listeria infection |
Granuloma formation - takes too long to form in immunocompromised |
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What transcription factor controls LLO production |
PRFA
Powerful regulator fuels assault |
Powerful regulator fuels assault |
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What is the word that describes how listeria infects neighbouring host cells using the actin rocket |
Paracytophagy |
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