E2 Order Actinomycetales Flashcards
What are the 3 important families in this order Actinomycetales?
- Actinomycetaceae
- Mycobacteriaceae
- Nocardiaceae
What is the gram stain of the order Actinomycetales?
Gram-positive
What is unique about the appearance of the order Actinomycetales?
Long branching filamentous rods
Sometimes beaded
(mycelia)
What are some culture characteristics of the family actinomycetaceae?
- Microaerophilic
- NOT-acid fast
- Formation of sulfur granules (rosetts)
What are sulfur granules composed of?
- Bacterial filaments
2. Calcium phosphate from the host
What are some characteristics of actinomycetaceae family infections?
- Chronic
- Soft & hard tissues
- Often with foreign bodies
What species has actinomyces bacteria as normal flora? Where?
Dog
Oropharynx & digestive tract
What are the clinical signs when a dog has an overgrowth of actinomyces bacteria?
Soft tissue swellings with sulfur granules
head & neck
What are some clinical presentations of actinomyces infections in cats (3)? Which one is most common?
- Bite wound abscess
- Pyothorax = most common
- Peritonitis
How can an actinomyces infection lead to pyothorax?
Deep chest wound
What type of antibiotics work well against actinomyces?
Penicillins
Is actinomyces normal flora in cattle? If so where?
Yes
Oral cavity
But can be opportunistic invaders of deep tissues
What is the name for the disease caused by actinomyces in cattle?
Lumpy Jaw
What is actinomyces infection associated with in cattle?
Foreign bodies
What two diseases does actinomyces cause in horses?
- Fistulous withers
2. Poll evil
What two diseases can actinomyces cause in swine although rare?
- Suppurative mastitis
2. Cystitis in older sows
What pathological process occurs in cattle with actinomyces infections?
Proliferative osteomyelitis
Is there a vaccine for actinomyces bovis?
No
What is another genus of the actinomycetaceae family?
Arcanobacterium
What is the only species of arcanobacterium of veterinary importance?
Arcanobacterium pyogenes
What role does arcanobacterium pyogenes play in animal health?
Commensal of the skin, upper respiratory tract and genitals
What diseases can arcanobacterium pyogenes cause if it enters deep tissues (4)?
- Mastitis
- Arthritis (green caseous pus)
- Placentitis
- Polyarthritis
What is another genus of gram-positive filamentous bacteria?
Nocardia
Where is Nocardia typically found?
Soil
What is special about Nocardia’s metabolism?
Obligate aerobe
What is the most important veterinary species of Nocardia?
Nocardia asteroides
How does Nocardia asteroides cause infections?
- Dirt in wounds
- Inhalation
- Ingestion
What animals can be infected with Nocardia asteroides?
Mammals
rare in birds
What cells are infected by Nocardia asteroides?
Phagocytes
What disease does Nocardia asteroides cause in cattle?
Mastitis
What diseases does Nocardia asteroides cause in dogs & cats (2)?
- Localized skin infections
2. Generalized = pyothroax (high mortality)
What is are common clinical findings with Nocardia asteroides infection (2)?
Small white nodules on organs
What drug is NOT a good choice for Nocardia asteroides infection?
Penicillin
strongly resistant
Is Nocardia asteroides zoonotic?
No
What is another gram positive branching filamentous bacteria (D)?
Dermatophilus
What is special about Dermatophilus?
It forms spores!
zoospores = flagella
Where is Dermatophilus commonly found?
Africa & India in the soil
What form of Dermatophilus is infectious?
Zoospores
What disease does Dermatophilus congolensis cause?
(Dermatophilosis) Horses =Rain scald =Grease heel Sheep = Lumpy wool =Strawberry footrot
Where is the reservoir for Dermatophilus congolensis?
Infected animals
not the soil
What causes increased infections of Dermatophilus congolensis?
Wet weather
Is Dermatophilus congolensis zoonotic?
Yes!
= Rare but can happen
(Remember to wear PPE)
