Listeria

Question 1

Is listeria gram positive or negative?

Answer 1

Gram positive rods- usually occur in chains

Question 2

Catalase _____Oxidase_____

Answer 2

catalase positive oxidase negative

Question 3

True/False: Listeria is spore forming and non motile?

Answer 3

False! Listeria is non spore forming and motile

Question 4

Is listeria an anerobe or aerobe?

Answer 4

Facultative anaerobe

Question 5

Listeria are facultative _____ parasites

Answer 5

intracellular- survival in macrophages or hepatocytes

Question 6

What pathogenesis does Listeria cause?

Answer 6

septicemia, encephalitis, and abortions

Question 7

What does ActA do?

Answer 7

intracellular movement

Question 8

What are the adhesions of listeria?

Answer 8

internalins, ActA, and protein 60

Question 9

What is the main virulence factor of Listeria and what does it do?

Answer 9

Listeriolysin OVERY IMPORTANT- can induce apoptosis of the cell- lysis of ferritin vacuolespore forming lysis factor. They create pores and the bacteria gets into the phagosome. To get out of the phagosome, Listeria punches a hole in the membrane and is able to escape. Then the bacteria uses ActA to travel through the cytoplasm to the next cell

Question 10

What is a cellular product of Listeria that breaks down phospholipids for membrane lysis?

Answer 10

Phospholipase C

Question 11

How does Listeria surivie in the intestinal lumen?

Answer 11

Bile salt hydrolase

Question 12

Intestinal Pathogenesis for Listeria

Answer 12

1. bacteria is ingested in decaying soil2. Many are killed by gastric acids3. If they survive, attach to epithelium,M cells, and phagocytic cells4. Once in the phagocytes, they move through the blood stream

Question 13

What can listeria cause in Pregnant females?

Answer 13

abortion or calves will be born with CNS signs- this is deterined by host immunity

Question 14

How does Listeria cause outbreaks in humans?

Answer 14

Food borne diseasemeningitis is the most common manifestationpregnant women- still births, preterm labor, infant with systemic infection

Question 15

What products may humans ingest that are contaminated?

Answer 15

dairy products that are infected with listeria from and asymptomatic cowListeria can withstand refrigeration

Question 16

Who are predisposed to disease from Listeria?

Answer 16

humans- immunosupressedanimals- neonates and preganat animals

Question 17

What kind of immune response do we want against Listeria?

Answer 17

mainly cell mediataed- since bacteria lives in cellshumoral can play a role

Question 18

Is there a vaccine for Listeria?

Answer 18

No

Question 19

What will you see in a gram stain of Listeria

Answer 19

Gram positive short rods with rounded ends. Some cells may be curved

Question 20

What lowtemperature is Listeria still mobile at?

Answer 20

25 degrees celsiusUmbrella pattern of motility

Question 21

How do you treat Listeria?

Answer 21

antimicrobial treatmentThere are NO vaccinesTherapy is often of little use