Unit 3: Actinobacillus Flashcards Preview

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Flashcards in Unit 3: Actinobacillus Deck (56)
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1
Q

On gram stain, what does the genus Actinobacillus look like?

A

small, gram-negative, pleomorphic coccabacilli

2
Q

On MacConkey’s what do colonies of Actinobacillus look like?

A

they produce small colonies if they do grow

3
Q

What does Actinobacillus lignieresii cause and in what species?

A

Cattle Wooden tongue - granulomatous, tumor-like infections, usually in the head and neck area

4
Q

What is the best environment for Actinobacillus lignieresii to grow in?

A

with serum in the media and primary cultures grow much better with an atmosphere of 10% CO2 in air

5
Q

What is the natural habitat of Actinobacillus lignieresii?

A

commensal of the buccal mucous membrane of cattle and sheep

6
Q

How does Actinobacillus lignieresii infect cattle

A

enters deeper tissues via wounds in the buccal epithelium

7
Q

What is the pathogenesis of an Actinobacillus lignieresii infection in cattle?

A
  1. Granulomatous abscesses form in any part of the body most frequently in the soft tissue of the lower jaw and neck 2. The abscesses eventually break through to the skin creating a deep ulcer that will not heal 3. If untreated, the ulcers tend to enlarge and additional ulcers may form 4. The organism may spread to internal organs, lung, and lymphoid tissue
8
Q

What allows Actinobacillus lignieresii to form granules?

A

a glycocalyx or capsule that cements the organism together

9
Q

What immune responses are important against Actinobacillus lignieresii infections?

A

humoral and cell mediated immune responses

10
Q

True or False: Many cattle have antibody against Actinobacillus lignieresii.

A

True

11
Q

How is infection caused by Actinobacillus lignieresii treated?

A

Debridement and local injections of aqueous iodine, streptomycin, tetracycline, and sulfas

12
Q

What is the cause of shigellosis?

A

Actinobacillus equuli

13
Q

What animals does shigellosis infect?

A

foals

14
Q

In adults, what does Actinobacillus equuli cause?

A

verminous aneurysms

15
Q

How does Actinobacillus equuli grow on culture?

A

it grows readily and abundantly on ordinary media Inconsistent growth on MacConkey’s (small colonies)

16
Q

What do colonies of Actinobacillus equuli look like?

A

slimy and mucoid, non-hemolytic except for subspecies haemolytica

17
Q

What is the natural habitat for Actinobacillus equuli?

A

the oral cavity and intestinal tract of normal horses

18
Q

What is the general pathogenesis of Actinobacillus equuli infection?

A

It is an opportunist. Disease is sporadic and usually only occurs in debilitated or stressed horses. Foals can contract the infection as they pass through the birth canal of infected mares. There is some indication that in-utero transmission occurs. Whatever the source, the organism becomes septicemic in foals

19
Q

What percentage of foals die of equulosis within 24 hours of birth and what lesion is associated with it?

A

1/3 - severe enteritis

20
Q

What percentage of foals die of equulosis within 4 days of birth and what lesions are associated with it?

A

2/3 - severe purulent nephritis with multiple small abscesses throughout the kidney cortex. Leg joints are frequently affected

21
Q

What is the pathogenesis of infection of Actinobacillus equuli in adult horses?

A

The organism may gain access to the blood when the larvae of Strongylus vulgaris migrates into the blood vessels from the intestine. Verminous aneurysms in the mesenteric arteries caused by migrating strongylus larvae are frequently infected with this organism. Infected horses often have a septicemia

22
Q

Can horses develop immunity against Actinobacillus equuli?

A

no - there is not enough time to develop much of an immune response

23
Q

Is there a vaccine for Actinobacillus equuli?

A

no - there is an experimental autogenous bacterin

24
Q

How is Actinobacillus equuli infection treated?

A

Streptomycin, penicillin, but caution should be used when using strongly bactericidal antibiotics

25
Q

What does Actinobacillus pleuropneumoniae cause and in what species?

A

Contagious pleuropneumonia (chronic) in swine (an acute respiratory disease that can become chronic)

26
Q

What type are most isolates of Actinobacillus pleuropneumoniae and what do they require to grow?

A

Biotype 1 and they require V factor to grow

27
Q

What does Biotype 2 of Actinobacillus pleuropneumoniae require for growth?

A

nothing

28
Q

What do colonies of Actinobacillus pleuropneumoniae look like?

A

relatively small at 2-3 days and hemolytic but the degree of hemolysis varies considerably

29
Q

What serotypes of Actinobacillus pleuropneumoniae predominate in the US?

A

serotypes 1, 3, 5, 7

30
Q

What toxins does Actinobacillus pleuropneumoniae produce and what do they have a high degree of homology to?

A

four RTX type toxins (Apx1, Apx2, Apx3, Apx4); the alpha hemolysin of E. coli and the leukotoxin of Mannheimia haemolytica

31
Q

Which RTX toxin of Actinobacillus pleuropneumoniae only grow in vivo?

A

Apx4

32
Q

What is the natural habitat of Actinobacillus pleuropneumoniae?

A

it is carried in the upper respiratory tract of swine

33
Q

In endemically infected herds, when are piglets infected with Actinobacillus pleuropneumoniae?

A

as colostral immunity wanes and mild disease usually results

34
Q

What does the acute form of Actinobacillus pleuropneumoniae look like in older susceptible swine?

A

it is an exudative and proliferative bronchopneumonia with fibrinous pleuritis along with anorexia, emesis, fever, and hemorrhaging from the mouth and nose

35
Q

When pigs are infected with the peracute form of Actinobacillus pleuropneumoniae how quickly can death occur?

A

within 8 hours

36
Q

Pigs that recover from an Actinobacillus pleuropneumoniae infection have what lesions remaining?

A

abcesses and pleural adhesions

37
Q

How do pigs develop immunity to an Actinobacillus pleuropneumoniae infection?

A

they have to survive it

38
Q

Are there any bacterins against Actinobacillus pleuropneumoniae infection?

A

yes against serotypes 1 and 5

39
Q

What is the advised treatment for Actinobacillus pleuropneumoniae infections?

A

penicillin, tetracycline, and tiamulin but the organism develops resistance easily

40
Q

What does Actinobacillus suis cause in 1-8 week old pigs?

A

fatal acute septicemia

41
Q

In older pigs, what has Actinobacillus suis been associated with?

A

arthritis, pneumonia, subcutaneous abscesses and a variety of other infections

42
Q

What do colonies of Actinobacillus suis look like?

A

small, beta hemolytic colonies

43
Q

What is required for growth of Actinobacillus suis cultures?

A

none - it does not need a staph nurse or NAD

44
Q

Does Actinobacillus suis grow on MacConkey?

A

yes

45
Q

What toxins does Actinobacillus suis produce?

A

RTX toxins (Apx1 and Apx2)

46
Q

What is the natural habitat of Actinobacillus suis?

A

it is carried in the tonsils and nasal passages of healthy pigs at any age and can also be recovered from the vagina of sows

47
Q

What is the pathogenesis of Actinobacillus suis infection?

A

Infection probably occurs via the upper respiratory tract, but invasion through skin lesions or other routes cannot be ruled out. The organism spreads rapidly throughout the body causing septicemia with acute death in young pigs and arthritis, pneumonia, and skin lesions in pigs older than 3 months of age

48
Q

How is Actinobacillus suis infection in pigs be treated?

A

with antibiotics, but it is difficult to treat in time to save the pigs

49
Q

What does Actinobacillus salpingitidis cause and in what species?

A

salpingitis and peritonitis in laying hens

50
Q

Where is Actinobacillus seminis found?

A

in sheep in south Africa

51
Q

Where does Actinobacillus seminis localize?

A

in the epididymis and testes

52
Q

What does Acintobacillus seminis cause?

A

abortion in sheep and decreased fertility in the ram

53
Q

What is the natural habitat of Actinobacillus seminis?

A

it is a normalpart of the microbial flora of the preputial and penile mucosa of the ram

54
Q

What does Actinobacillus actinomycetemcomitans cause and in what species?

A

human endocarditis, meningitis, osteomyelitis, and periodontitis

55
Q

What are the main ecological sites of residence for Actinobacillus actinomycetemcomitans?

A

dental plaque, periodontal pockets, and gingival sulci

56
Q

What type of toxin does Actinobacillus actinomycetemcomitans produce?

A

a potent leukotoxin

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