Lecture 10 Flashcards

1
Q

What is the bio containment level for Actinomycetales?

A

level 1-2

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2
Q

Are Actinomycetales gram positive or negative?

A

Positive

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3
Q

What is the appearance of Actinomycetales, Nocardia?

A

Filamentous rods

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4
Q

Describe the appearance of Trueperella pyogenes

A

Pleomorphic gram positive croci-rods

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5
Q

Describe the appearance of Dermatophilus congolensis

A

Branching filaments

Fragment into packets of coccoid cells

Tram tract appearance*

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6
Q

Where is streptomyces found?

A

Soil

Usually non-pathogenic

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7
Q

Where is actinomyces found on the host? (3)

A

Mucous membranes

Nasal cavity

Pharynx

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8
Q

Where is Trueperella found on the host? (3)

A

Mucous membranes

Nasal cavity

Pharynx

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9
Q

Where is Dermatophilus congolensis found?

A

Maintained by carrier animals

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10
Q

Where is Nocardia found?

A

Envr organism

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11
Q

What are the virulence factors for Trueperella pyogenes? (4)

A

Pyolysin - cytotoxic

Neuraminidases, collagen binding PROs & fimbriae - for adhesion

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12
Q

What are the virulence factors for Dermatophilus congolensis?

A

Protesases - tissue breakdown

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13
Q

Describe the sulfur granules from Actinomyces

A

Centrally located bacteria surrounded by clouds of eosinophilic material

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14
Q

What disease does Acintomyces bovis cause in cattle?

A

Lumpy jaw

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15
Q

Describe the pathogenesis of lumpy jaw caused by Actinomyces bovis

A

A. bovis is a normal oral microbiota

Course feed (ex: plant awns) cause lesions in the oral cavity (usually the mandible)

A. bovis will invade

New periosteal bone will form in response to infection

Fibrosis occurs

Forms a hard & immovable painless mass, draining tracts may develop

Usually the mass is painful unless it involves the teeth

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16
Q

How do you tx lumpy jaw caused by Actinomyces bovis?

A

Debridement & penicillin

May need to drain, if so consult surgeon

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17
Q

What is the px of lumpy jaw caused by Actinomyces bovis?

A

Tx may arrest growth of lesion, but regression is usually minimal (new bone formation is permanent)

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18
Q

What is the management to prevent lumpy jaw caused by Actinomyces bovis?

A

Allow access to high quality feed

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19
Q

How does Actinomyces spp normally present in dogs & Cats?

A

As a pyothorax

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20
Q

Describe the pathogenesis of Actinomyces infection in dogs & cats

A

Normal member of microbiota

When there is some sort of injury to the oropharynx (bite wound, grass awns, FBs etc.) then the bacteria enter the wound

Normally presents as a pyothorax

Pulmonary infections can occur when they aspirate the awn
&
Abdominal infections can occur following ingestion & migration of the awn out of the GIT into the abdomen

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21
Q

What are the symptoms of a dog or cat with Actinomyces?

A

Variable

May have firm or fluctuant lesions
May have draining tracts
Head & cervical region most commonly effected

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22
Q

What do the lesions contain in a dog or cat with Actinomyces infection?

A

Serosanguinous to purulent material

Contain sulfur granules

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23
Q

How do you tx Actinomyces infection in a dog or cat?

A

Drain/aspirate the material often

Remove the cause (i.e. remove the grass awn)

Long term penicillin

24
Q

Describe the appearance of Actinomyces israelii?

A

Filamentous rods & gram positive

25
Q

Describe the pathogenesis of Dermatophilus congolensis

A

Microbe lives on skin

There is damage to the skin on the animal

The bacteria invade the lesion

When there is a lot of moisture, there is release of zoospores which are then mechanically transmitted b/w animals

results in crusting of the skin

(usually seen in the fall & winter months in warmer regions)

26
Q

What is required for infection of Dermatophilus congolensis to occur? (3)

A

Carrier animal present

There is an abundance of moisture present

There is skin damage

27
Q

How does Dermatophilus congolensis present as an infection?

A

Superficial infections of a wide range of animals

28
Q

What spp does Dermatophilus congolensis effect?

A

Wide range including horses, cattle & sheep

29
Q

What are the symptoms of Dermatophilus congolensis in horses? (2)

A

Rain scald - crusting of skin on back

Dew poisoning - crusting of skin on lower extremities when horses are kept on wet pastures

30
Q

What are the symptoms of Dermatophilus congolensis in sheep? (2)

A

Lumpy wool

Strawberry footrot on distal extremities

31
Q

How does Dermatophilus congolensis present in dogs? (2)

A

Exudative skin disease

Superficial on haired skin

32
Q

How does Dermatophilus congolensis present in cats? (2)

A

Exudative skin disease

Often abscessation

33
Q

How do you tx Exudative skin disease in dogs & cats? (3)

A

Keep skin dry & clean

Bathe & remove crusts

Penicillin

34
Q

How do you tx Dermatophilus congolensis in sheep? (2)

A

Topical disinfectants

A/bs (depending on spp)

35
Q

How do you prevent Dermatophilus congolensis in sheep? (2)

A

Remove from wet envr

Discard crusts (source of infection for other animals)

36
Q

How is Trueperella pyogenes caused?

A

Suppurative infections

37
Q

How does Trueperella pyogenes present in calves?

A

Laryngeal abscesses

38
Q

How does Trueperella pyogenes present in cattle?

A

Liver abscesses & a component of bovine respect disease

39
Q

How does Trueperella pyogenes present in pigs? (3)

A

Arthritis

Osteomyelitis

Subcutaneous abscesses

40
Q

What spp do Trueperella pyogenes infections tend to occur with?

A

Fusobacterium necrophorum

41
Q

Describe the pathogenesis of Trueperella pyogenes in cattle

A

Cattle have a highly fermentable diet

Ruminal acidosis occurs

Bacteria colonize the damaged rumen tissue

Bacteria translocate from the rumen into the portal venous sys which can result in abscessation & thrombosis of the caudal vena cava

When the abscesses burst they release bacteria which act as an emboli

Septic emboli are transported from the R side of the heart to the lungs

Bacteria get stuck in capillary beds & set up secondary sites of infection

Septic emboli are usually fatal & rupture of the caudal vena cava is fatal

42
Q

Where is Actinobaculum suis found?

A

Commensal organism of the urogenital tract in pigs

43
Q

How does Actinobaculum suis present as an infection? (4)

A

Clinical signs vary

UTI in pigs

Typically afebrile

Hematuria & pyuria

May be found dead due to acute renal failure

44
Q

Describe the pathogenesis of Actinobaculum suis in pigs

A

Causes UTI in pigs

Ascending infection of the kidney

45
Q

What is the tx for Actinobaculum suis infection in pigs? (3)

A

Penicillins

Management:
Good hygiene & provide sufficient water

46
Q

How do you collect samples when suspecting Actinomyces & Nocardia spp infections?

A

Collect exudates, aspirates & other samples via thoracentesis

47
Q

How do you collect samples when suspecting Dermatophilus congolensis?

A

Crusts

48
Q

How do you collect samples when suspecting Actinobaculum suis?

A

Urine

49
Q

How should you handle samples for Actinomycetales? (2)

A

Tissue for history in 10% formalin

DO NOT freeze

50
Q

How does the lab identify Actinomyces? (3)

A

Smear of aspirates - look for granules in pus

Grows well on blood agar

Sequence if required

51
Q

How does the lab identify Dermatophilus congolensis?

A

Smears of aspirates - look for tram tracks

52
Q

How does the lab identify Nocardia spp?

A

Look for filamentous rods in acid fast

53
Q

Is Actinomyces zoonotic?

A

Yes

A. israelii causes infections in humans

Component of oral microbiota

54
Q

Is Trueperella pyogenes zoonotic?

A

Rarely in humans

55
Q

Is Dermatophilus congolensis zoonotic?

A

Skin infections possible in people if they come into contact with infected animals & have skin trauma

56
Q

How do you tx Nocardia spp? (2)

A

Sulfonamides or sulfa/trimethoprim