rhodococcus, actinomycetales (actinomyces, dermatophilus, trueperella) Flashcards
characteristics of rhodococcus
- part of normal microbiota
- gram positive coccobacilli
- aerobic and facultatively anaerobic
- level 2
R. equi horses
host: foals
dz: bronchopneumonia, abscesses
causes: suppurative pneumonia (acute or chronic)
- enteric dz in 50% of foals
zoonotic through environment not horse
control: can live in fecal-contaminated soil so clean up manure
treatment: rifampin and macrolide drugs
- resistant to penicillins and cephalosporins
R. equi cat
dz: cutaneous lesions
causes: non-painful pyogranulomatous inflammation
- abscesses with draining tracts and lesions on parenchymal organs
treatment: surgical drainage, antimicobials
characteristics of actinomyces
- part of normal oral microbiota
- gram-positive filamentous rods
- non-spore forming
- branching filaments
A. bovis
host: cattle and small ruminants
dz: lumpy jaw
- invades with tissue damage (sharp feed)
treatment: debridement, penicillin
A. ssp. and nocardia spp. (environmental)
host: dog, cat
dz: pyothorax, SC infections, foreign body associated infections
- invades via damage to the oropharynx
nocardia inhibits phagosome-lysosome fusion in macrophages
treatment: remove the foreign body, penicillin
actinobaculum suis
host: pigs
dz: UTI
- usually commensal of urinary tract
causes: hematuria, pyuria, acute renal failure -> progresses to pyelonephritis
TREATMENT: good hygiene, sufficient water, penicillins
characteristics of Dermatophilus
- lives on the skin
- moisture stimulates the release of zoospores
- gram-positive zoospores in 2 parallel lines
virulence of Dermatophilus
proteases
Dermatophilus congolensis - horse, cattle
dz: rain scalding
- crusting lesions on back or lower extremities
- maintained by carrier animals
- enters via damaged skin
treatment: topical disinfectant, penicillins, remove the animal from wet environment
Dermatophilus congolensis - sheep
DZ: lumpy wool, strawberry footrot
- mycotic dermatitis
Dermatophilus congolensis - dog, cat
dz: dermatophilosis
- exudative skin diseases
dogs = superficial on haired skin
cats = often abscessation
zoonotic - skin infection secondary to trauma
characteristics of Trueperella
- pleomorphic gram-positive coccobacilli
- host associated
virulence of Trueperella
pylosin cytotoxin
neuraminidase and other adhesion tools
T. pyogenes
host: cattle, sheep, pigs
dz: suppurative infections
- no classical presentation, variety of pus dzs
- often involves fusobacterium necrophourm
- spreads in body via septic emboli
treatment: penicillins, tetracyclins
