Sketchy Micro: Listeria Monocytogenes

Question 1

What kind of bacteria is Listeria monocytogenes?

Answer 1

Gram-positive bacillus

Think of the violet ornaments behind Santa – they’re also rod-shaped.

Question 2

What lab tests help identify Listeria monocytogenes?

Answer 2

It is beta-hemolytic (just like the beta-light bulb on top of the Christmas tree) and it is catalase positive (like the cat on the floor by Santa’s feet).

Question 3

How does Listeria move?

Answer 3

First remember that Listeria is a facultative intracellular microbe, so it can exist inside and outside host cells. Inside host cells it uses actin to polymerize and jut itself forward (like the actin-rockets in Santa’s bag and on the floor), while outside cells it uses flagella to tumble (like the ornaments tumbling off the tree).

Question 4

Why is Listeria able to contaminate so many food products?

Answer 4

It can survive in freezing temperatures, including in the fridge.

(Think of the icicles and milk/cheese left out for Santa.)

Question 5

_____________ are discouraged from eating soft cheeses for fear of Listeria contamination.

Answer 5

Pregnant women (think of the pregnant woman in the corner)

Question 6

Listeria is the 3rd most common cause of ________________ in infants.

Answer 6

meningitis (like the meningitis helmet that the baby is wearing)

Question 7

How should you treat meningitis from Listeria?

Answer 7

Ampicillin

Think of the amp and guitar in the corner.