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38 Cards in this Set
- Front
- Back
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Pathogen characteristics of Actinobacteria
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Gram +
High G+C content in their DNA (51-65%) |
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Major pathogens of Actinobacteria can be found in this Order...
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Actinomycetales - many are pyogenic (pus producers)
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Pathogen characteristics of Corynebacterium
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Gram +, High G+C content
Mycolic acids in cell wall Pleomorphic Coryneform Catalase +, Oxidase - Falculatative anaerobes Fastidious (requires enriched growth media to grow) |
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What is meant by the term "Coryneform"?
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Knotted rod, V-shaped, "Chinese Characters", Palisades
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Epidemiology of Corynebacterium
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Commensals on mucus membranes
Predisposing factors: trauma C. pseudotuberculosis survives well in the environment |
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Pathogenesis of Corynebacterium
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Opportunistic pathogen
Pus producer/Pyogenic (not C. bovis) |
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Pathogenesis of Corynebacteria pseudotuberculosis
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Opportunistic pathogen
Pyogenic Intracellular pathogen Toxic cell wall lipid components Phospholipase D toxin --> destroys our cell membranes |
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Clinical signs of Corynebacteria pseudotuberculosis
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Sheep/goats:
Caseous lymphdentitis - entry through cuts, infection spread by pus from ruptured abscesses and oral/nasal secretions; enlarged submandibular/regional lymph nodes Horses and cattle: Ulcerative lymphangitis - slow/chronic inflammation of lymph vessels, particularly legs Nitrate reducing biotype of C. pseudotuberculosis |
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Distribution of Corynebacteria pseudotuberculosis
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Unknown in Ireland in sheep/goats
Global distribution in horses/cattle - exotic infection in Ireland |
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Pathogenesis of Corynebacteria renale
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Opportunistic pathogen
Pyogenic Fimbriae Urease Ammonia - increase pH or urine, promoting growth Shed in infected urine and survive on pasture |
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Clinical signs of Corynebacteria renale
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Cattle: Cystitis (bladder) and pyelonephritis (kidney)
Rams/Wethers: ulcerative balanoposthitis (inflammation of glans and prepuce) |
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Diagnosis of Corynebacterium species
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Routine culture
Biochemical tests for differentiation - API-Coryne system, some PCR tests available CAMP test - C. pseudotuberculosis is CAMP test NEGATIVE |
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Treatment/Control of Corynebacteria pseudotuberculosis
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Exclusion of suspect imports
In low prevalence countries: Eradication - repeated ELISA testing and culling In high prevalence countries: try to control disease through hygiene and vaccination |
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Pathogen characteristics of Rhodococcus equi
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Gram + cocci or rods
Salmon pink colonies, mucoid, non-haemolytic Aerobic NOT fastidious Mycolic acids |
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Epidemiology of Rhodococcus equi
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Soil saprophyte, intestinal tract
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Pathogenesis of Rhodococcus equi
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Opportunistic pathogen - inhalation of dust
Falcultative intracellular Plasmid-based virulence factors |
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Clinical signs of Rhodococcus equi
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Foals: suppurative bronchopseumonia of foals 1-4 months old; "rattles"
Abscesses in older animals |
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Diagnosis of Rhodococcus equi
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Culture and microscopic examination of secretions
Colonies salmon-pink, mucoid, non-haemolytic CAMP test POSITIVE with Staphylococcus aureus |
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Treatment/Control of Rhodococcus equi
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Prevent build-up in environment
Avoid dusty conditions Prolonged antibiotic course NO available vaccine |
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Characteristics of Nocardia asteroides
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Saprophyte of soil
Produces aerial mycelium with chains of arthrospores Looks like chalk on Blood Agar |
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Pathogenesis of Nocardia asteroides
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Aerobic
Facultative intracellular pathogen Modified ZN + |
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Clinical signs of Nocardia asteroides
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Occasional cause of mastitis (treat with prolonged antibiotic course)
Canine nocardiosis - suppurative pleuritis or peritonitis |
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Actinomycetaceae characteristics
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Contains genera Actinomyces, Truperella, and Actinobacterium
Gram + Many have distinctive branching filaments Modified ZN - Relatively slow growing, require Blood Agar Opportunists Pyogranulomatous reactions |
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Characteristics of Trueperella pyogenes
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Coryneform morphology
Hazy maemolysis, pin-point colonies Pitting of agar in Loeffler's slope Gram + Filamentous branching Falcultative anaerobe |
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Pathogenesis of Trueperella pyogenes
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Opportunistic
Pyolysin - hemolytic exotoxin that target cholesterol Proteases Pyogranulomatous reactions |
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Clinical signs of Trueperella pyogenes
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Suppurative lesions in any organ
Cattle, sheep, pigs: abortion (most common cause in Ireland) Summer mastitis: foul smelling, mixed infections with anaerobes |
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Clinical signs of Actinomyces bovis
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Cattle: Actinomycosis - "lumpy jaw"
Anaerobic, localized lesion that contains sulphur granules |
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Clinical signs of Actinomyces viscosus
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Dogs: canine actinomycosis - cutaneous pyogranulomas, pyothorax and pyogranulomatous pleural lesions
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Characteristics of Dermatophilus congolensis
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Motile coccal zoospores
Smears from scabs stained with Giemsa to see zoospore tram-tracks Persist in foci in skin Survive in scabs in environment |
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Pathogenesis of Dermatophilus congolensis
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Carboxiphylic: 5-10% CO2 for culture growth
Predisposing factors: prolonged wetting, abrasions |
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Clinical signs of Dermatophilus congolensis
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Pustules/scabs on face, limbs and/or back
Skin infections in large animals - most in subtropical climates; "Mud fever", Rain scald in horses Uncommon but not exotic in Ireland |
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Treatment of Dermatophilus congolensis
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Parenteral antibiotics
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Name the bacteria
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Corynebacteria pseudotuberculosis
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Name this bacteria
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Rhodococcus equi
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Name this bacteria
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Nocardia asteroide
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Name this bacteria
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Trueperella pyogenes
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Name the genus of the bacterium that causes these conditions.
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Actinomyces spp.
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Name the bacteria
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Dermatophilus congolensis
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