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Flashcards in Listeria Deck (45):
1

Is listeria gram positive or negative?

Gram positive rods- usually occur in chains

2

Catalase _____ Oxidase_____

catalase positive oxidase negative

3

Is listeria host specific?

no- it can affect a lot of different species Critical species to know- Ruminants

4

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

False! Listeria is non spore forming and motile

5

What kind of flagella does Listeria have?

peritrichous

6

Is listeria an anerobe or aerobe?

Facultative anaerobe

7

What are the two most important pathogen species?

Listeria monocytogenes( MOST IMPORTANT) and Listeria invanovii

8

How do you distinguish between L. monocytogenes and L. invanovii?

CAMP test! L. monocytogenes- CAMP positive with S. aureus L. invanovii- CAMP positive with R. equi

9

Listeria are facultative _____ parasites

intracellular- survival in macrophages or hepatocytes

10

What pathogenesis does Listeria cause?

septicemia, encephalitis, and abortions

11

What does ActA do?

intracellular movement

12

What are Internalins?

induces phagocytosis- aids in phagocytosis and allows the bacteria to live in the cellular environment

13

What are the adhesions of listeria?

internalins, ActA, and protein 60

14

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

Listeriolysin O

VERY IMPORTANT

- can induce apoptosis of the cell- lysis of ferritin vacuoles 

pore 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

15

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

Phospholipase C 

16

How does Listeria surivie in the intestinal lumen?

Bile salt hydrolase 

17

Does Listeria have variability?

YES! very high variability. Many serovars

18

What is the normal habitat for Listeria?

Decaying plant matter 

19

How is Listeria transmitted?

Fecal oral route 

Ingestion of contaminated feed 

nasal mucosa 

20

How do ruminants get Listeria?

When they eat poor quality silage that has fermented and decayed 

21

Intestinal Pathogenesis for Listeria

1. bacteria is ingested in decaying soil

2. Many are killed by gastric acids 

3. If they survive, attach to epithelium, M cells, and phagocytic cells

4. Once in the phagocytes, they move through the blood stream 

22

Central Nervous System pathogenesis for Listeria 

1. damaged oral, nasal or ocular mucosa

2. Bacteria goes into the facial nerves (trigeminal) and gets into the CNS

 

23

What can listeria cause in Pregnant females?

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

24

How can you tell if Listeria has gotten into the CNS?

do a cerebrospinal tap- fluid will be cloudy due to tons of inflammation

You will see tons of mononuclear cells

Perivascular cuffing 

25

What will septicemic Listeria cause?

necrosis in the liver and spleen 

26

What is the main pathology that Listeria causes in Ruminants?

Encephalitis (Circling disease)

The bacteria is causing damage to the brain 

tendency to circle in one direction

Facial paralysis 

Death in 2-3 days 

27

Is treatment of Encephalitis in ruminants effective?

Not really- by the time you see signs there is already too much damage to the brain 

28

What are some characteristics of Encephalitis?

perivascular cuffing:

a lot of inflammatory cells around the vessels

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29

What does Listeria cause in ruminants?

Septicemia- if bacteria in GI tract

Abortion- not common (sporadic, localize in placenta)

Conjunctivits- related to elevated feed bunkers

Mastitis

30

What can Listeria cause in the liver?

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31

When are horses susceptible to getting Listeria septicemia?

When there has been failure of passive transfer 

32

What happens if dogs, cats, or swine get Listeria?

Very mild, often asymptomatic 

33

How does Listeria cause outbreaks in humans?

Food borne disease

meningitis is the most common manifestation 

pregnant women- still births, preterm labor, infant with systemic infection

34

What products may humans ingest that are contaminated?

dairy products that are infected with listeria from and asymptomatic cow 

Listeria can withstand refrigeration 

35

What seaons are more typical to see Listeria 

winter and spring- can withstand cold temperatures 

Can survive in silage even during a freeze 

36

When an animal is _____ the bacteria has an easier time getting into the host and causing disease 

stressed 

37

Who are predisposed to disease from Listeria?

humans- immunosupressed

animals- neonates and preganat animals 

38

What kind of immune response do we want against Listeria?

mainly cell mediataed- since bacteria lives in cells

humoral can play a role 

39

Is there a vaccine for Listeria?

No 

40

What will you see in a gram stain of Listeria 

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

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41

What different medias can you use to isolate Listeria?

Listeria enriched media- Columbia CNA agar, Oxford medium 

Sheep Blood agar at 35 degrees celsius- cold enrichment. Casues a narrow zone of Beta hemolysis

Grows best with increased CO2

 

 

42

Is Listeria CAMP positive or negative?

positive with Staph aureus 

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43

What low temperature is Listeria still mobile at?

25 degrees celsius

Umbrella pattern of motility 

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44

How do you treat Listeria?

antimicrobial treatment

There are NO vaccines

Therapy is often of little use

45

How do you control Listeria?

Don't feed bad silage

reduce stress

isolation of affected animals