Actinomyces, Nocardia, Dermatophilus

Question 1

What species does Actinomyces bovis typically effect?

Answer 1

cattle and horses

Question 2

What does Actinomyces bovis cause in cattle?

Answer 2

lumpy jaw (granulomatous osteomyelitis)

Question 3

What does Actinomyces bovis cause in horses?

Answer 3

fistulous withers and poll evil infection

Question 4

How does Actinomyces bovis show up on a gram stain?

Answer 4

gram positive filamentous or short rods that appear as cocci

Question 5

What type of organism is Actinomyces bovis in relation to oxygen?

Answer 5

extreme microaerophile

Question 6

What forms in tissues as a result of Actinomyces bovis and why?

Answer 6

‘sulfer granules’ because the organisms produce glycocalyx that cements them together

Question 7

What is the natural habitat of Actinomyces bovis?

Answer 7

it is an obligate parasite of the oropharynx and digestive tract

Question 8

What is the pathogenesis of granulomatous osteomyelitis in cattle?

Answer 8

the organism enters the dental alveoli or through trauma wounds in the gums or oral mucosa, then the lesions enlarge and produce a large necrotic are that eventually drains to the exterior, the draining pus contains the ‘sulfer granules’ that are assocciated with this lesion

Question 9

What other organism is commonly associated with lumpy jaw infections in cattle?

Answer 9

Trueperella pyogenes

Question 10

Fistulous withers is an infection of the _______ _______.

Answer 10

supra-atlantoid bursae

Question 11

Poll evil is an infection of the ___________ ________.

Answer 11

supraspinous bursae

Question 12

What type of horses usually get fistulous withers or poll evil?

Answer 12

horses that are used as work animals because their collars can cause irritation in these areas

Question 13

What other organism is commonly associated with fistulous withers and poll evil?

Answer 13

Brucella abortus

Question 14

What type of immunity is associated with Actinomyces bovis?

Answer 14

cell-mediated but once the lesions form it is difficult for the immune system

Question 15

Is Actinomyces bovis treatable?

Answer 15

yes with extended antimicrobial treatment (antibiotics combined with IV sodium iodide) but lumpy jaw is hard to treat due to the osteomyelitis

Question 16

What is the most common cause of actinomycosis in dogs?

Answer 16

Actinomyces viscosus

Question 17

What is the natural habitat of Actinomyces viscosus?

Answer 17

it is an obligate parasite of the oropharynx and digestive tract

Question 18

What type of organism is Actinomyces viscosus in regards to oxygen?

Answer 18

aerobic

Question 19

What lesions are associated with Actinomyces viscosus?

Answer 19

pyothorax

Question 20

What is the pathogenesis of Actinomyces viscosus?

Answer 20

it invades wounds in dogs frequently in the head or neck areas leading to pyothorax

Question 21

What is found in the pus in lesions due to Actinomyces viscosus?

Answer 21

sulfur granules

Question 22

What is Actinomyces viscosus associated with in hamsters and humans?

Answer 22

peridontal disease

Question 23

What type of immunity is associated with Actinomyces viscosus?

Answer 23

cell-mediated immunity

Question 24

Is Actinomyces viscosus treatable?

Answer 24

yes with antimicrobials

Question 25

What does Actinomyces suis cause in sows?

Answer 25

granulomatous and supparative mammary gland lesions

Question 26

What is the natural habitat of Actinomyces suis?

Answer 26

oropharynx in pigs

Question 27

What is the pathogenesis of Actinomyces suis?

Answer 27

it is associated with superficial wounds of the mammary gland during suckling

Question 28

What is the 'typical lesion' associated with Actinomyces suis?

Answer 28

actinomycotic granuloma which contains sulfer granules when it drains

Question 29

What are the lesions associated with actinomycosis in humans?

Answer 29

first peridontal disease, then as it spreads thoracic and pulmonary infections, abdominal infections, and genital infecitons

Question 30

What is used to treat actinomycosis in humans?

Answer 30

penicillin

Question 31

How does the genus Nocardia show up on gram stain?

Answer 31

gram-positive rods that form branching filaments

Question 32

What type of organism is the genus Nocardia in regards to oxygen?

Answer 32

aerobic

Question 33

What lesions does Nocardia asteroides cause in dogs and cats?

Answer 33

suppurative thoracic and subcutaneous lesions

Question 34

What disease in cattle is Nocardia asteroides associated with?

Answer 34

mastitis

Question 35

Nocardia asteroides and Corynebacterium pseudotuberculosis create similar colonies, what key characteristic differentiates the two?

Answer 35

Nocardia asteroides takes longer to grow - typically 3-6 days

Question 36

What do colonies of Nocardia asteroides look like?

Answer 36

they are yellow to orange and often appear dry and rough

Question 37

How does Nocardia asteroides respond to a catalase test?

Answer 37

it is catalase positive

Question 38

How does Nocardia asteroides respond to acid-fast staining?

Answer 38

it is partially acid-fast

Question 39

What is the natural habitat of Nocardia asteroides?

Answer 39

soil

Question 40

How is Nocardia asteroides transmitted?

Answer 40

via wounds, ingestion, and inhalation

Question 41

What lesion is associated with infection of Nocardia asteroides in the respiratory system in dogs and cats?

Answer 41

pyothorax

Question 42

What is observed with subcutaneous infections in Nocardia asteroides?

Answer 42

draining tracts

Question 43

Are infections of Nocardia asteroides localized or do they metastasize?

Answer 43

they usually metastasize

Question 44

How is Nocardia asteroides treated?

Answer 44

with surgical drainage or debridement, and aggressive antimicrobial therapy

Question 45

How is Nocardia asteroides treated in cattle specifically?

Answer 45

it isn't because it is not responsive to antimicrobial treatment so the animals are culled

Question 46

What species is Nocaria braziliensis associated with?

Answer 46

dogs and humans

Question 47

What humans typically get nocardiosis?

Answer 47

immunocompromised humans such as AIDS patients, cancer patients, chronic alcoholics, and transplant recipients

Question 48

What species of Nocardia typically infects humans?

Answer 48

Nocardia asteroides

Question 49

What clinical signs and lesions are associated with nocardiosis in humans?

Answer 49

supparative lesions and abscesses; headaches and convulsions

Question 50

What is the cause of dermatophilosis?

Answer 50

Dermatophilus congolensis

Question 51

What does Dermatophilus congolensis look like on gram stain?

Answer 51

gram positive rods

Question 52

What is the life cycle of Dermatophilus congolensis?

Answer 52

it forms filamentous groups of organisms which release motile zoospores that grow and form a germ tube and eventually new filaments which then divide

Question 53

What is the natural habitat of Dermatophilus congolensis?

Answer 53

soil

Question 54

What species does Dermatophilus congolensis infect?

Answer 54

cattle, dogs, horses, sheep, deer, and captive wild animals

Question 55

What season is associated with a heightened amount of Dermatophilus congolensis infections?

Answer 55

rainy season in tropical areas

Question 56

What is the pathogenesis of Dermatophilus congolensis?

Answer 56

trauma such as tick bites are often associated with disease, serum and cell debris form into large, thick scabs

Question 57

How is Dermatophilus congolensis diagnosed?

Answer 57

a smear of the exudate under the scabs can be air dried and stained with Giemsa stain

Question 58

What is the treatment for Dermatophilus congolensis?

Answer 58

penicillin