Listeria (Exam 5) Flashcards
What is the oxygen requirement for Listeria?
facultative anaerobe
Listeria is a gram (negative/positive) (spore/non-spore)-forming ________.
gram-positive non-spore forming rod
Listeria is (motile/non-motile).
motile (4-6 peritrichous flagella)
Listeria ________ causes a serious, food-borne illness in humans.
L. monocytogenes
Where can Listeria monocytogenes can found?
soil, decaying veggies, feces
What temperatures can Listeria grow in?
psychotropic (refrigeration temps)
(T/F) Listeria can survive intracellularly.
True
Listeria monocytogenes are highly infectious with (high/low) pathogenicity.
low
Listeria monocytogenes can be cultured on blood agar and under ________ for neural listeriosis (brain tissue)
cold-enrichment
Match the virulence factor of Listeria to its function:
- pore-forming toxin; phagosome escape
- adhesion & internalization (“zipper mechanism”)
- escape from vacuole & cell-to-cell spread
- actin polymerization
- Listeriolysin O
- Internalins
- Phospholipase C
- ActA protein
What kind of Listeriosis infection is most common?
subclinical
How is Listeria transmitted?
ingestion
Subclinical Listeriosis occurs by ingestion which penetrates the intestinal epithelium and travels to the _______.
liver
Subclinical Listeriosis is mediated by what type of immunity?
cell-mediated
Listeriosis is associated with 3 syndromes:
- neural/encephalitic
- abortion
- septicemia + visceral abscess
Neural or Encephalitic Listeriosis is commonly called “__________” or “________”.
Silage Sickness
Circling Disease
The main lesion with Neural or Encephalitic Listeriosis is:
meningoencephalitis
Meningoencephalitis caused by Listeria leads to what 3 clinical signs?
- unidirectional circling
- unilateral facial paralysis
- corneal opacity
Which species of animal most commonly develops the Neural form of Listeriosis?
ruminants (cattle, sheep, goats)
Transmission of Neural Listeriosis is associated with poor-quality or spoiled _________.
silage
Abortion due to Listeriosis occurs when 2 ________ target and cross the placental barrier in pregnant animals.
invasion proteins
Abortion caused by Listeriosis occurs sporadically in _________, is a flock condition in _________, and very rare in _______.
cattle
sheep
dogs
How is Abortive Listeriosis controlled?
change spoiled silage or dilute with better silage
Which form of Listeriosis is the LEAST common?
Visceral Listeriosis (septicemia w/ visceral abscesses)
Visceral Listeriosis ONLY occurs in:
neonates
Septicemia and ________ are the most common signs of Visceral Listeriosis.
gastroenteritis
What is the characteristic lesion of Visceral Listeriosis?
focal hepatic necrosis
(T/F) Humans are susceptible to Listeriosis.
True (especially infants, elderly, immunosuppressed, pregnant)
______ & ______ products are animal sources of Human Listeriosis.
meat & dairy
Field-grown products such as lettuce, vegetables, and cantaloupes are associated with Human Listeriosis due to _______ contamination.
manure
(T/F) Human Listeriosis can occur by direct contact with an infected animal.
False
