LISTERIA

Question 1

What is the only species of Listeria pathogenic for warm-blooded animals and humans?

Answer 1

Listeria monocytogenes

Question 2

Give the morphology of Listeria.

Answer 2

• Gram +, non-acid fast, small rods
• Shows slight clubbing, diphtheroid appearance, coccoid forms found
• Peritrichous flagella with tumbling motility

Question 3

Listeria can be gram negative in what circumstances?

Answer 3

In young cultures and in old cultures

Question 4

In gelatin, what is the appearance of L. monocytogenes?

Answer 4

Inverted fir tree

Question 5

Listeria monocytogenes produces catalase. True or False?

Answer 5

True

Question 6

Describe the colonies of L. monocytogenes.

Answer 6

• Grows on most ordinary media though growth never abundant
• Deep colonies minute points with narrow zone of beta-hemolysis
• Surface colonies small, flat, bluish-white, transparent

Question 7

Mode of infection of neural and visceral form of L. monocytogenes are the same. True or False?

Answer 7

False, different

Question 8

Give the antigens present in L. monocytogenes.

Answer 8

1. 15 O antigens
2. 5 H antigens
3. 16 serotypes (not antigen?)
4. 14 subtypes (not antigen?)

Question 9

In neural form of Listeria infection, infection is via?

Answer 9

Branches of trigeminal nerve and the eye, nose, and oropharynx

Question 10

In visceral form of Listeria infection, what is the major mode?

Answer 10

Ingestion

Question 11

Most Listeria infections are endogenous. True or False?

Answer 11

False, exogenous

Question 12

What is the common disease induced by Listeria?

Answer 12

Listeriosis

Question 13

In neural form, what is the common disease induced by Listeria?

Answer 13

Circling disease

Question 14

What form of Listeria infection is most common in ruminants?

Answer 14

Neural form

Question 15

Increase in ____ consumption thought to contribute to listeriosis.

Answer 15

iron