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| − | ===Overview=== | + | {{frontpage |
| | + | |pagetitle =Actinomycetes |
| | + | |pagebody = Actinomycetes organisms are gram positive bacteria that grow slowly on media and produce branching filaments. They are associated with opportunistic infections causing inflammatory responses and granulomatous reactions; animal pathogens include ''Actinomyces, Arcanobacterium, Actinobaculum, Nocardia'' and ''Dermatophilus''. |
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| − | *Gram positive bacteria
| + | Actinomycetes organisms are non-motile, non-spore-forming bacteria which are anaerobic or facultative anaerobes that typically colonise mucous membranes. They will grow on enriched media and are non-acid fast, Modified Ziehl-Neelson negative when stained. |
| − | *Grow slowly on media and produce branching filaments
| + | Clinically, this class of organisms includes ''Micropolyspora faeni and Thermactinomyces vulgaris'' - these are implicated in [[Extrinsic Allergic Bronchio-Alveolitis|Bovine Farmers Lung]] and ''Thermactinomyces vulgaris'' is associated with the pathology of [[Recurrent Airway Obstruction|RAO]] in horses. |
| − | *Opportunistic infections causing inflammatory responses and granulomatous reactions
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| − | *Animal pathogens include ''Actinomyces, Arcanobacterium, Actinobaculum, Nocardia'' and ''Dermatophilus''
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| − | ===''Arcanobacterium, Actinomyces'' and ''Actinobaculum'' species=== | + | |contenttitle =Content |
| | + | |contentbody =<big><b> |
| | + | <categorytree mode=pages>Actinomycetes</categorytree> |
| | + | </b></big> |
| | + | |logo =bugs-logo copy.png |
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| − | *Non-motile, non-spore-forming bacteria
| + | [[Category:Bacterial Organisms]] |
| − | *Anaerobic or facultative anaerobes
| + | [[Category:Gram_positive_bacteria]] |
| − | *Grow on enriched media; non-acid fast
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| − | *Colonise mucous membranes
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| − | *Modified Ziehl-Neelson negative
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| − | <big>'''''<ncl style=bullet maxdepth=2 headings=bullet headstart=2 showcats=1 showarts=0>Category:{{PAGENAME}}</ncl></big>
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| − | ''[[Arcanobacterium pyogenes]]''
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| − | ''[[:Category:Actinomyces|Actinomyces]]''
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| − | ===''[[Actinobaculum suis]]''===
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| − | ===''[[Nocardia]]''===
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| − | ===''Dermatophilus congolensis''===
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| − | *Filamentous, branching actinomycete
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| − | *Aerobic
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| − | *Produces motile zoospores
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| − | *No growth on Sabouraud dextrose agar
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| − | *Dermatophilosis most prevalent in tropical and subtropical regions
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| − | *Organisms found in scabs and in foci in skin of carrier animals
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| − | *Dormant zoospores become activated when moisture and temperature levels are favourable
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| − | *Zoospores may survive 3 years in scabs
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| − | *'''Pathogenicity''':
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| − | **Does not usually invade healthy skin
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| − | **Entrance after trauma or persistent wetting
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| − | **Activated zoospores produce germ tubes which develop into filaments which invade the epidermis
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| − | **Invasion causes an accute inflammatory response with many [[Neutrophils - WikiBlood|neutrophils]]
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| − | **Microabscesses are formed in the skin
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| − | **Raised crusts develop in the affected regions
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| − | *[[Bacterial skin infections - Pathology#Dermatophilosis|'''Pathology''']]
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| − | *'''Diagnosis''':
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| − | **Giemsa-stained smears from scabs reveal branching filaments containing zoospores
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| − | **Immunofluorescence
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| − | **Scab material can be cultured on blood agar at 37 degrees centigrade, 2.5-10% carbon dioxide for 5 days
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| − | **Zoospores can be cultured
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| − | **After incubation, colonies are yellow and haemolytic (after 48 hours); they later become rough and yellow, and gain a mucoid appearance
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| − | **No growth on Sabouraud dectrose agar
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| − | *'''Clinical infections''':
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| − | **Infection usually confined to epidermis
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| − | **Dermatophilosis
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| − | **Disease most prevalent in young animals
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| − | **Damage to the skin predisposes to infection; blood-sucking insects also thought to be involved in transmission
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| − | **Lesions after heavy rainfall predominantly affect dorsum of farm animals
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| − | **Papules, serous, exudative matting of hair, raised crusty scabs
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| − | **Scab formation more prominent in sheep and cattle than in horses
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| − | **Lesions may resolve within weeks if dry weather, or may progress
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| − | *'''Treatment''':
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| − | **Parenteral antibiotics e.g oxytetracycline, pr penicillin-streptomycin combinations
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| − | *''Micropolyspora faeni and Thermactinomyces vulgaris'' in [[Bronchi and Bronchioles Inflammatory - Pathology#Extrinsic Allergic Bronchio-alveolitis|Bovine Farmers Lung]]
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| − | *''Thermactinomyces vulgaris'' may cause [[Bronchi and Bronchioles Inflammatory - Pathology#Chronic obstructive pulmonary disease (COPD)|COPD]]
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| − | [[Category:Bacteria]] | |