Lecture 17 Flashcards

1
Q

What is the appearance of Salmonella on an agar plate?

A

Grey colonies

Classic Enterobacteriaeae morphology - smooth, round margins

Gram negative

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2
Q

Where is Salmonella found?

A

Intestinal microbiota

Many of the spp vary in Canada by province, so you need to be familiar with the spp that you are working with in your province

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3
Q

What are the virulence factors for Salmonella?

A

Salmonella Pathogenicity Islands (SPI) - gene clusters with antimicrobial resistance

Fimbriae - adherence & colonization

3 Secretion sys - when they attach to enterocytes they inj effector molecules in the cells allowing macrophages to engulf them & enabling the bacteria to colonize other tissues. Once in the tissues they perform the phagolysosome complex & resist dying

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4
Q

What probs does Salmonella Dublin cause in cattle? (5)

A

Septicemia in < 1 wk old calves

Acute enteritis in older calves & adults

Abortion

Chornic enteritis in older cows

Terminal dry gangrene - leads to DIC –> ischema & necrosis

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5
Q

How do you manage Salmonella Dublin to prevent its effects? (3)

A

Clean calving areas

Rodent control

Vaccination

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6
Q

What spp does Salmonella cholerasuis effect?

A

Pigs - host adapted

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7
Q

What probs does Salmonella cholerasuis cause in pigs?

A

Sepsis

Enterocolitis

Secondary infections following bacteria (pneumonia & hepatitis)

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8
Q

How do you prevent Salmonella cholerasuis in pigs? (2)

A

Reduce stress to reduce shedding by carriers

Autogenous bacterins (vaccine)

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9
Q

What spp does Salmonella pullout effect? & what happens if you see it?

A

Birds - host adapted

Contact CFIA ASAP

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10
Q

What spp does Salmonella Type effect? & how do they get it?

A

People - host adapted

Contaminated food & water

In the west, assoc with travel

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11
Q

How do you dx Yersinia in the lab?

A

CIN agar - highly selective for yersinia specifically

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12
Q

What is the metabolism of Yersinia?

A

Lactose non-fermenting

Motile

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13
Q

What disease does Yersinia pestis cause in people?

A

Plague/Black death

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14
Q

How do people get Yersinia pestis? (3)

A
  1. Direct contact with rodents
  2. Direct contact with infective flea
  3. Airborne from people (pneumonic plague) - becomes aerosolized
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15
Q

What is the sylvatic plague? What spp is highly susceptible?

A

Lifecycle b/w wild rodents & fleas

Prairie dogs are highly susceptible

Can serve as a source for our domestic animals

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16
Q

What are the 3 forms of Yersinia pestis in cats?

A

Bubonic - lymphadenomegaly, submandibular LN effected (may look like abscess)

Septicemic - may or may not follow bubonic form, due to hematogenous spread, death in 1-2 days

Pneumonic - may follow haematogenous dissemination, may be due to inhaling infectious droplets, zoonotic risk, highly contagious (beware of the hissing cat)

17
Q

What are the symptoms of Yersisnia pestis in companion animals?

A

High fever

Lethargy

Anorexia

18
Q

How do you tx Yersinia pestis in companion animals?

A

Streptomycin **

(there are others)

Start with parenteral a/bs then switch to oral (IV –> oral)

19
Q

What disease does Yersinia pseudotuberculosis cause in ruminants?

A

Sporadic disease with abscessation of internal organs

Enteric infections under stressful conditions - cold & wet weather, poor diet & stressful procedures

Some abortions

20
Q

What are the 2 forms of pseduotuberculosis in guinea pigs?

A

Septicemic form

Nodules in internal organs

21
Q

How do humans get Yersinia enterocolitica?

A

Assoc with eating undercooked pro

22
Q

What organisms in the Enterobacteriaceae family cause therapeutic & resistance issues? (5)

A

Klebsiella

Citrobacter

Enterobacter

Serratia

Morganella

23
Q

What samples do you collect to test for Salmonella? (2)

A

Feces

Blood for serology

24
Q

What samples do you collect for Yersinia pestis? (3)

A

Lymph node aspirates

Edematous tissue

Blood

No re-capping needles & wear gloves

25
Q

What sample do you collect for testing Enterobacteriaceae?

A

Affected tissues

26
Q

How does the lab dx Salmonella? (2)

A

Cultures

Serology

27
Q

How does the lab dx Enterobacteriaceae? (5)

A

Blood agar

MacConkey agar

Colony morphology

Biochemical tests

MALDI-TOF

28
Q

What tests does the lab need to perform if they suspect an outbreak of an Enterobacteriaceae?

A

DNA fingerprinting to determine the strain type

29
Q

Does salmonella pose a zoonotic risk?

A

Yes

Foodborne & infected/colonized animals

30
Q

How is Yersinia petsis transmitted to humans?

A

Exudates

Resp droplets

Fleas

31
Q

How do you tx Enterobacteriaceae?

A

Based on susceptibility testing - a lot of intrinsic resistance

Avoid:
Beta-lactamases
Flurorquinolone resistance