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MY Bacteriology exam 2 > Listeria > Flashcards

Listeria Flashcards

1
Q

Is listeria gram positive or negative?

A

Gram positive rods- usually occur in chains

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2
Q

Catalase _____ Oxidase_____

A

catalase positive oxidase negative

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3
Q

Is listeria host specific?

A

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

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4
Q

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

A

False! Listeria is non spore forming and motile

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5
Q

What kind of flagella does Listeria have?

A

peritrichous

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6
Q

Is listeria an anerobe or aerobe?

A

Facultative anaerobe

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7
Q

What are the two most important pathogen species?

A

Listeria monocytogenes( MOST IMPORTANT) and Listeria invanovii

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8
Q

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

A

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

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9
Q

Listeria are facultative _____ parasites

A

intracellular- survival in macrophages or hepatocytes

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10
Q

What pathogenesis does Listeria cause?

A

septicemia, encephalitis, and abortions

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11
Q

What does ActA do?

A

intracellular movement

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12
Q

What are Internalins?

A

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

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13
Q

What are the adhesions of listeria?

A

internalins, ActA, and protein 60

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14
Q

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

A

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

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15
Q

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

A

Phospholipase C

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16
Q

How does Listeria surivie in the intestinal lumen?

A

Bile salt hydrolase

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17
Q

Does Listeria have variability?

A

YES! very high variability. Many serovars

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18
Q

What is the normal habitat for Listeria?

A

Decaying plant matter

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19
Q

How is Listeria transmitted?

A

Fecal oral route

Ingestion of contaminated feed

nasal mucosa

20
Q

How do ruminants get Listeria?

A

When they eat poor quality silage that has fermented and decayed

21
Q

Intestinal Pathogenesis for Listeria

A
  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
Q

Central Nervous System pathogenesis for Listeria

A
  1. damaged oral, nasal or ocular mucosa
  2. Bacteria goes into the facial nerves (trigeminal) and gets into the CNS
23
Q

What can listeria cause in Pregnant females?

A

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

24
Q

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

A

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

You will see tons of mononuclear cells

Perivascular cuffing

25
Q

What will septicemic Listeria cause?

A

necrosis in the liver and spleen

26
Q

What is the main pathology that Listeria causes in Ruminants?

A

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
Q

Is treatment of Encephalitis in ruminants effective?

A

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

28
Q

What are some characteristics of Encephalitis?

A

perivascular cuffing:

a lot of inflammatory cells around the vessels

29
Q

What does Listeria cause in ruminants?

A

Septicemia- if bacteria in GI tract

Abortion- not common (sporadic, localize in placenta)

Conjunctivits- related to elevated feed bunkers

Mastitis

30
Q

What can Listeria cause in the liver?

A
31
Q

When are horses susceptible to getting Listeria septicemia?

A

When there has been failure of passive transfer

32
Q

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

A

Very mild, often asymptomatic

33
Q

How does Listeria cause outbreaks in humans?

A

Food borne disease

meningitis is the most common manifestation

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

34
Q

What products may humans ingest that are contaminated?

A

dairy products that are infected with listeria from and asymptomatic cow

Listeria can withstand refrigeration

35
Q

What seaons are more typical to see Listeria

A

winter and spring- can withstand cold temperatures

Can survive in silage even during a freeze

36
Q

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

A

stressed

37
Q

Who are predisposed to disease from Listeria?

A

humans- immunosupressed

animals- neonates and preganat animals

38
Q

What kind of immune response do we want against Listeria?

A

mainly cell mediataed- since bacteria lives in cells

humoral can play a role

39
Q

Is there a vaccine for Listeria?

A

No

40
Q

What will you see in a gram stain of Listeria

A

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

41
Q

What different medias can you use to isolate Listeria?

A

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
Q

Is Listeria CAMP positive or negative?

A

positive with Staph aureus

43
Q

What low temperature is Listeria still mobile at?

A

25 degrees celsius

Umbrella pattern of motility

44
Q

How do you treat Listeria?

A

antimicrobial treatment

There are NO vaccines

Therapy is often of little use

45
Q

How do you control Listeria?

A

Don’t feed bad silage

reduce stress

isolation of affected animals

MY Bacteriology exam 2 (18 decks)

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