Difference between revisions of "Actinomycetes"
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| − | # | + | <big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big> |
| + | <big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big> | ||
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| + | *Cause [[Peritoneal cavity - inflammatory#In dogs|peritonitis in dogs]] and [[Peritoneal cavity - inflammatory#In cattle|peritonitis in cattle]] and [[Peritoneal cavity - inflammatory#In pigs|peritonitis in pigs]] | ||
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| + | *''Nocardia'' is involved in [[Peritoneal cavity - inflammatory#In dogs|peritonitis]] and [[Bacterial infections#Nocardiosis|pleuritis]] in dogs | ||
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| + | *''Micropolyspora faeni and Thermactinomyces vulgaris'' in [[Bronchi and bronchioles - inflammatory#Extrinsic Allergic Bronchio-alveolitis|Bovine Farmers Lung]] | ||
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| + | *''Thermactinomyces vulgaris'' may cause [[Bronchi and bronchioles - inflammatory#Chronic obstructive pulmonary disease (COPD)|COPD]] | ||
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| + | * ''Actinomyces'' may cause [[General Pathology - Chronic Inflammation#Granulomatous Inflammation|granulomatous inflammation]]. | ||
| + | ** E.g. ''Actinomyces bovis'' -the cause of [[Oral Cavity - Teeth#Mandibular Osteomyelitis|lumpy jaw]] and in [[Bones - inflammatory#Osteomyelitis|osteomyelitis]], may extend to surrounding [[Muscles - inflammatory#Actinomycosis bovis|muscles]] | ||
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| + | *''Actinomyces pyogenes'' in [[Bones - inflammatory#Osteomyelitis|osteomyelitis]] | ||
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| + | *In [[Pleural cavity and membranes - inflammatory#Pyothorax (Thoracic empyema)|pyothorax]] | ||
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| + | *Isolated from closed cases of [[Bursae and Tendons - inflammatory#Poll Evil and Fistulous Withers|Poll Evil and Fistulous Withers]] | ||
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| + | ===Overview=== | ||
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| + | *Gram positive bacteria | ||
| + | *Grow slowly on media and produce branching filaments | ||
| + | *Opportunistic infections causing inflammatory responses and granulomatous reactions | ||
| + | *Animal pathogens include ''Actinomyces, Arcanobacterium, Actinobaculum, Nocardia'' and ''Dermatophilus'' | ||
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| + | ===''Actinomyces, Arcanobacterium'' and ''Actinobaculum'' species=== | ||
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| + | *Non-motile, non-spore-forming bacteria | ||
| + | *Anaerobic or facultative anaerobes | ||
| + | *Grow on enriched media; non-acid fast | ||
| + | *Colonise mucous membranes | ||
| + | |||
| + | *''Arcanobacterium pyogenes'' | ||
| + | **Characteristics: | ||
| + | ***Formerly known as ''Actinomyces pyogenes'' and ''Corynebacterium pyogenes'' | ||
| + | ***Small rod | ||
| + | ***Grows slowly on blood agar to produce small, white colonies surrounded by a zone of beta-haemolysis after 48 hours | ||
| + | ***Coryneform morphology, like Chinese characters; may be curved with slightly swollen ends | ||
| + | ***Found in nasopharyngeal mucosa and genital tract of cattle, sheep, pigs | ||
| + | **Pathogenicity'' | ||
| + | ***Opportunistic infections following injury or viral/mycoplasma infection in ruminants and pigs | ||
| + | ***Extracellular toxins including haemolysin, proteases, DNase and neurominidase | ||
| + | ***Haemolytic toxin, pyolysin, member of the thiol-activated cytolysins (pore-forming toxins); possibly cytotoxic to phagocytic cells | ||
| + | **Clinical infections: | ||
| + | ***Suppurative infections | ||
| + | ***Abscesses especially in liver | ||
| + | ***Pyometra | ||
| + | ***Summer mastitis | ||
| + | ***Ovine foot disease | ||
| + | ***Umbilical infections | ||
| + | ***Pneumonia | ||
| + | |||
| + | *''Actinomyces'' | ||
| + | *Usually long and filamentous branching Gram positive rods | ||
| + | **''Actinomyces bovis'' found naturally in oral cavity of cattle; prefers anaerobic conditions but not strict anaerobe; penetrates injured tissues to cause granulomatous lesions of soft tissues and bone, causing lumpy jaw; organisms found in sulphur granules | ||
| + | **''Actinomyces viscosus'' commensal of oral cavity of dogs and humans; causes localised abscesses of skin or granulomatous lesions in thorax which may spread to abdomen causing pyothorax; rods contained in soft grey granules which release the organism when squashed | ||
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| + | *''Actinbaculum suis'' in preputial mucosa of boars | ||
| + | *''Actinobaculum'' have a coryneform morphology | ||
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| + | ''Nocardia'' | ||
| + | |||
| + | *Aerobic short branching rods | ||
| + | *Cell wall contains mycolic acids (hence slightly acid fast) | ||
| + | *''Nocardia asteroides'' found in soil | ||
| + | *Causes granulomatous lesions in animals | ||
| + | *Survives and multiplies in macrophages | ||
| + | *Chronic, progressive disease | ||
| + | *Lesions difficult to treat due to resistance of organisms to many antimicrobials (e.g. penicillins) | ||
Revision as of 14:03, 17 February 2008
- Cause peritonitis in dogs and peritonitis in cattle and peritonitis in pigs
- Nocardia is involved in peritonitis and pleuritis in dogs
- Micropolyspora faeni and Thermactinomyces vulgaris in Bovine Farmers Lung
- Thermactinomyces vulgaris may cause COPD
- Actinomyces may cause granulomatous inflammation.
- E.g. Actinomyces bovis -the cause of lumpy jaw and in osteomyelitis, may extend to surrounding muscles
- Actinomyces pyogenes in osteomyelitis
- In pyothorax
- Isolated from closed cases of Poll Evil and Fistulous Withers
Overview
- Gram positive bacteria
- Grow slowly on media and produce branching filaments
- Opportunistic infections causing inflammatory responses and granulomatous reactions
- Animal pathogens include Actinomyces, Arcanobacterium, Actinobaculum, Nocardia and Dermatophilus
Actinomyces, Arcanobacterium and Actinobaculum species
- Non-motile, non-spore-forming bacteria
- Anaerobic or facultative anaerobes
- Grow on enriched media; non-acid fast
- Colonise mucous membranes
- Arcanobacterium pyogenes
- Characteristics:
- Formerly known as Actinomyces pyogenes and Corynebacterium pyogenes
- Small rod
- Grows slowly on blood agar to produce small, white colonies surrounded by a zone of beta-haemolysis after 48 hours
- Coryneform morphology, like Chinese characters; may be curved with slightly swollen ends
- Found in nasopharyngeal mucosa and genital tract of cattle, sheep, pigs
- Pathogenicity
- Opportunistic infections following injury or viral/mycoplasma infection in ruminants and pigs
- Extracellular toxins including haemolysin, proteases, DNase and neurominidase
- Haemolytic toxin, pyolysin, member of the thiol-activated cytolysins (pore-forming toxins); possibly cytotoxic to phagocytic cells
- Clinical infections:
- Suppurative infections
- Abscesses especially in liver
- Pyometra
- Summer mastitis
- Ovine foot disease
- Umbilical infections
- Pneumonia
- Characteristics:
- Actinomyces
- Usually long and filamentous branching Gram positive rods
- Actinomyces bovis found naturally in oral cavity of cattle; prefers anaerobic conditions but not strict anaerobe; penetrates injured tissues to cause granulomatous lesions of soft tissues and bone, causing lumpy jaw; organisms found in sulphur granules
- Actinomyces viscosus commensal of oral cavity of dogs and humans; causes localised abscesses of skin or granulomatous lesions in thorax which may spread to abdomen causing pyothorax; rods contained in soft grey granules which release the organism when squashed
- Actinbaculum suis in preputial mucosa of boars
- Actinobaculum have a coryneform morphology
Nocardia
- Aerobic short branching rods
- Cell wall contains mycolic acids (hence slightly acid fast)
- Nocardia asteroides found in soil
- Causes granulomatous lesions in animals
- Survives and multiplies in macrophages
- Chronic, progressive disease
- Lesions difficult to treat due to resistance of organisms to many antimicrobials (e.g. penicillins)