Lesson 3 (VMCB) Flashcards
media for nocardia species
Sabouraud dextrose agar
A 5-year-old dairy cow presents with acute mastitis, characterized by a foul-smelling purulent secretion from the udder. Culture results indicate a Gram-positive, facultative anaerobic bacterium with pitting on Loeffler’s serum slope. What is the most likely causative agent?
Trueperella pyogenes
A beef cow presents with a firm, non-painful swelling on the mandible that exudes pus containing sulfur granules. Radiographs reveal osteomyelitis. Which pathogen is the most likely cause?
A) Nocardia asteroides
B) Actinobaculum suis
C) Actinomyces bovis
D) Trueperella pyogenes
Actinomyces bovis
A dog presents with respiratory distress, fever, and multiple draining subcutaneous abscesses. Cytology reveals Gram-positive, partially acid-fast filamentous bacteria. What is the most likely causative agent?
Nocardia asteroides
A group of cattle develops exudative dermatitis with scab formation after a prolonged rainy season. Giemsa-stained smears reveal Gram-positive filamentous bacteria with coccoid zoospores. What is the most likely diagnosis?
Dermatophilosis
A pregnant sow presents with hematuria, dysuria, and arching of the back. The causative organism is an anaerobic, Gram-positive rod isolated from the urinary tract. What is the most likely pathogen?
Actinobaculum suis
Which Actinobacteria species is commonly associated with suppurative lesions and abscess formation in livestock?
Trueperella pyogenes
A horse with nocardiform placentitis caused by Crossiella equi is most likely to experience:
Abortion in late gestation
The primary virulence factor of Trueperella pyogenes that contributes to its pathogenicity is:
Pyolisin
The presence of club-shaped structures in histopathological sections is most characteristic of:
Actinomyces bovis
A distinguishing feature of Nocardia species is:
Partial acid-fast staining
Which of the following organisms does NOT grow on Sabouraud dextrose agar?
Dermatophilus congolensis
associated with equine nocardiform placentitis, leading to loss of the foal in approximately 50% of cases
Crossiella equi
long, slender, branching filaments with a tendency to fragment into rods and cocci in smears
nocardia sp.
species under genus nocardia
N. asteroides, N. farcinica
found in scabs and in foci on skin of carrier animals
Dermatophilus congolensis
atmospheric growth requirements of actinomyces
Anaerobic, or facultative anaerobic, capnophilic
atmospheric growth requirements of arcanobacterium pyogenes
Facultative anaerobic, and capnophilic
habitat of actinobaculum suis
Prepuce and preputial diverticulum of boars
their usual habitat are soils
nocardia sp.
produces pyolisin which is cytolytic for several cell types including neutrophils and macrophages, and is dermonecrotic and lethal for laboratory animals
Trueperella pyogenes
usual mode of infection by nocardia sp.
inhalation (or thru skin wounds or via teat canal)
produce germ tubes and these develop into filaments which invade the epidermis
Dermatophilus congolensis zoopores
reveals aggregates of filamentous organisms surrounded by eosinophilic club- shaped structures
lesions caused by Actinomyces bovis
selective growth enhancing media for Nocardia sp.
charcoal yeast extract medium
in which agar nocardia sp. yields dry, wrinkled, orange- coloured colonies after incubation for up to 5 days
Sabouraud dextrose agar
in which agar nocardia sp. Become white, powdery and firmly adherent to agar
blood agar
Specimens suitable for laboratory examination for dermatophilosis
scab material and samples of skin fixed in formalin
opportunistic pathogen and is a common cause of suppurative lesions in many domestic species worldwide
Trueperella pyogenes
chronic rarefying osteomyelitis following trauma to the mucosa from rough feed or through dental alveoli during tooth eruption
lumpy jaw
affects the urinary tract of pregnant sows, is transmitted at coitus and is potentially fatal
Actinobaculum suis
Etiology of Canine actinomycosis resulting to subcutaneous pyogranulomatous lesions and extensive fibrovascular
proliferation on the peritoneal or pleural surfaces
Actinomyces viscosus
causative agent of lumpy jaw
Actinomyces bovis
This specific disease, which affects the
urinary tract of pregnant sows, is transmitted at coitus and is potentially fatal.
Porcine cystitis and pyelonephritis
These bacteria are usually confined to the epidermis
Dermatophilus congolensis
Disease condition of Nocardia species associated with pigs
Abortion
