Lecture 11 Flashcards
What is the biocontainment level for Listeria?
2
What is the appearance of Listeria? (4)
Short
Gram positive rods
Can be coccoid
Beta hemolytic
Describe metabolism of Listeria
Facultative anaerobes
Growth is enhanced by CO2
Where is Listeria normally found? (6)
Normal microbiota component
Intestinal tract
Found in feces
Can be recovered form milk of sheep after lambing
Raw dairy & meat products
Decaying plant material
Describe how Listeria does in the envr?
Can survive for long periods
What are the virulence factors of Listeria? (4)
Internalin A - surface PRO which allows the organism to bind to the host cell receptors & be phagocytosed into a cell
Listerolysin O - involved lysis of phagosome enables escaping destruction from the phagosome & start to replicate in the cytoplasm of the cell
Phospholipase C - enables the cell to breakout of the vacuole & spread from cell to cell, works in conjunction with listerolysin O
Actin-polymerizing PRO (ActA) - hijacks host cell actin - forms pseudopods of the infected cell & creates invaginations in another cell to become encased in a double membrane. Once in the cell it can replicate
What is the pathogenesis of Circling disease from Listeria in ruminants?
Listeria is commonly found in the material (via faces & plant material)
Grows readily in decaying feed
Insufficient acidic silage can promote growth of these organisms
They become ingested with feed
Enter compromised barriers in the mouth - can occur after mucosal damage, teeth cutting & tooth loss
Submucosa –> trigeminal nerve –> brain
Disrupts BBB resulting in infection going undetected due to no inflammatory response
What are the symptoms of circling disease in ruminants?
Depression, then head tilting & circling
Can also see drooling, unilateral face paralysis, tongue hanging out of mouth
Will die within a few days
What disease does Listeria cause in ruminants? (3)
Circling disease
Also causes sepsis & abortions/complications during pregnancy
Does Listeria permanently effect fertility?
No, transient effect on fertility
How do you tx for Listeria in aborted fetuses in ruminants? (3)
Antimicrobial prophylaxis for other in herd with tetracycline has been used
Removed aborted tissues
Test silage
What pops does Listeria effect in people?
Pregnant women - abortion
Older adults
Compromised immune sys
How do people acquire Listeria? (3)
Uncooked meats & vegetables
Raw dairy products
Processed foods
It can grow in the fridge!
What pop is most susceptible to Listeria monocytogenes in poultry?
Young birds
How does Listeria monocytogenes present in poultry? (6)
Septicemia form - emaciation & diarrhea
Encephalitic form - depression, incoordination & other nervous signs
Disease assoc with cold & wet conditions
