Mycobacterium, Actinomycosis, and Nocardiosis

Question 1

What’s the causative agent of mycobacteriosis?

Answer 1

mycobacterium spp.
Cats: M. bovis and M. microti
Dogs: M. tuberculosis

Question 2

What are the clinical signs?

Answer 2

Cats: cutaneous nodules/ draining tracts; other non-specific signs – lethargy, anorexia, decreased body weight, respiratory distress
Dogs: mostly non-specific signs – lethargy anorexia, decreased body weight, coughing, dyspnea, vomiting, diarrhea

Question 3

Cats or dogs are are more commonly infected with mycobacterium?

Answer 3

Rare in dogs

Question 4

How is lesion morphology determined?

Answer 4

mostly due to host immune response rather than the strain
- tuberculoid lesion = macrophages at site of infections

Question 5

How is mycobacterium diagnosed?

Answer 5

• clinical suspicion
• geographical location
• identification of acid-fast bacilli
• intradermal tuberculin and M. bovis antibody testing = not helpful in cats,
• ID testing is also not helpful in dogs

Question 6

What’s the prognosis of mycobacterium in cats and dogs?

Answer 6

Cats: guarded, prolonged antibiotic therapy required
Dogs: grave, mostly euthanized due to disease progression

Question 7

What’s the health concern for myucobacterium?

Answer 7

zoonotic! reportable

Question 8

What’s feline/ canine leprosy?

Answer 8

The causative agent is Mycoplasma, but difficult to culture.

Cats:
- young cats: single or multiple SQ nodules, more likely to be ulcerated, more likely on the limbs
- old cats: slowly progressive, diffuse, non-ulcerated lesion more likely

Dogs: firm, non-painful well circumscribed dermal-SQ nodules, haired skin

Question 9

How is leprosy diagnosed?

Answer 9

• history, clinical suspicion, PCR

Question 10

How is leprosy treated?

Answer 10

Dogs: may spontaneously go into remission
Cats: need antibiotics

Question 11

What’s the prognosis of leprosy?

Answer 11

dogs: excellent, but persistent lesions could be disfiguring
cats: recurrence possible

Not a public health concern

Question 12

What’s the most common route of infection for actinomycosis?

Answer 12

Actinomyces = commensal bacteria, esp in GI tract (gum, mucus membranes)
- mostly associated with periodontal disease
- foreign body migrations
- bite wounds

Question 13

What are some clinical signs of actinomycosis?

Answer 13

pyogranulomatous lesions
- can be malodorous
- “sulfur granules” on exudates/ effusions

Question 14

How is actinomycosis treated?

Answer 14

Surgical debridement and antibiotics.
Dogs: thoracotomy + antibiotics
Cats: thoracic drainage + antibiotics

Question 15

What’s the prognosis of actinomycosis?

Answer 15

SQ or soft tissue infection, or cats with pyothorax - the prognosis is good
- dogs with thoracic disease = variable
- all reported CNS cases = fatal

Question 16

What’s the causative agent of actinomycosis?

Answer 16

Actinomyces spp
- facultatively anaerobic
- gram (+), non acid-fast, non-sporing
- branching filamentous bacteria

Question 17

How is actinomycosis diagnosed?

Answer 17

cytology - non-acid fast filamentous bacteria

Question 18

What’s the causative agent for Nocardiosis?

Answer 18

Nocardia spp
- gram (+)
- variably acid fast
- non-motile aerobic bacterium

Question 19

What are the clinical signs of Nocariosis?

Answer 19

Cutaneous/ SQ abscess (mycetomas)
- T cells needed to help halt systemic infection, but also leads to formation of granuloma
- can form draining tracts
- thoracic disease = pneumonia, pyothorax – signs of dyspnea, tachypnea, lethargy, weight loss, and fever

Question 20

How is nocardiosis diagnosed?

Answer 20

macroscopic and microscopic examination

Question 21

How is nocardiosis treated?

Answer 21

Similar to actinomycoses – debride, drainage, and antibiotics (prolonged therapy, 6-12m)
- if disseminated disease = grave prognosis, esp with CNS involvement

no infected pet to human transmission reported