Difference between revisions of "Actinomycetes"

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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]]
 
*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]]
−
 
−
*''Nocardia'' is involved in [[Peritoneal cavity - inflammatory#In dogs|peritonitis]] and [[Bacterial infections#Nocardiosis|pleuritis]] in dogs
 
−
 
 
*''Micropolyspora faeni and Thermactinomyces vulgaris'' in [[Bronchi and bronchioles - inflammatory#Extrinsic Allergic Bronchio-alveolitis|Bovine Farmers Lung]]
 
*''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]]
 
*''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]].
 
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** 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]]
 
−
 
−
*''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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===''Actinomyces, Arcanobacterium'' and ''Actinobaculum'' species===
+
===''Arcanobacterium, Actinomyces'' and ''Actinobaculum'' species===
  
 
*Non-motile, non-spore-forming bacteria
 
*Non-motile, non-spore-forming bacteria
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===''Arcanobacterium pyogenes''===
 
===''Arcanobacterium pyogenes''===
 +
 
*Characteristics:
 
*Characteristics:
 
**Formerly known as ''Actinomyces pyogenes'' and ''Corynebacterium pyogenes''
 
**Formerly known as ''Actinomyces pyogenes'' and ''Corynebacterium pyogenes''
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**Suppurative infections
 
**Suppurative infections
 
**Abscesses especially in liver
 
**Abscesses especially in liver
 +
**Lymphadenitis, [[Bones - inflammatory#Osteomyelitis|osteomyelitis]], peritonitis and neural abscessation
 
**Pyometra
 
**Pyometra
 
**Endometritis
 
**Endometritis
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**Umbilical infections
 
**Umbilical infections
 
**Suppurative pneumonia
 
**Suppurative pneumonia
 +
*Treatment:
 +
**Penicillin or broad spectrum antibiotics
 +
**Unclassified ''Actinomyces'' species isolated from closed cases of [[Bursae and Tendons - inflammatory#Poll Evil and Fistulous Withers|Poll Evil and Fistulous Withers]]
  
  
 
===''Actinomyces''===
 
===''Actinomyces''===
 +
 
*Usually long filamentous branching Gram positive rods
 
*Usually long filamentous branching Gram positive rods
 
*Anaerobic or facultativlyy anaerobic and capnophilic
 
*Anaerobic or facultativlyy anaerobic and capnophilic
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***Found naturally in oral cavity of cattle
 
***Found naturally in oral cavity of cattle
 
***Prefers anaerobic conditions but not strict anaerobe
 
***Prefers anaerobic conditions but not strict anaerobe
−
***Penetrates injured tissues to cause granulomatous lesions of soft tissues and bone, causing lumpy jaw
+
***Penetrates injured tissues to cause [[General Pathology - Chronic Inflammation#Granulomatous Inflammation|granulomatous inflammation]] lesions of soft tissues and bone, causing [[Oral Cavity - Teeth#Mandibular Osteomyelitis|lumpy jaw]]
 +
***Usually invades mandible to cause [[Bones - inflammatory#Osteomyelitis|osteomyelitis]] and may extend to surrounding [[Muscles - inflammatory#Actinomycosis bovis|muscles]]
 
***Organisms found in yellow sulphur granules
 
***Organisms found in yellow sulphur granules
 
***Club colony formation
 
***Club colony formation
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**''Actinomyces viscosus''
 
**''Actinomyces viscosus''
 
***Commensal of oral cavity of dogs and humans
 
***Commensal of oral cavity of dogs and humans
−
***Causes localised abscesses of skin or granulomatous lesions in thorax leading to pyothorax in dogs
+
***Canine actinomycosis
 +
***Causes localised subcutaneous pyogranulomatous lesions and fibrovascular proliferation of peritoneal and pleural surfaces in dogs
 +
***Leads to [[Pleural cavity and membranes - inflammatory#Pyothorax (Thoracic empyema)|pyothorax]]
 +
***Respiratory distress
 
***Cutaneous pustules in horses
 
***Cutaneous pustules in horses
 
***Abortion in cattle
 
***Abortion in cattle
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***Two types of colonies: large and smooth colonies with V, Y and T configurations or small and rough colonies with short branching filaments
 
***Two types of colonies: large and smooth colonies with V, Y and T configurations or small and rough colonies with short branching filaments
 
***Grow in 10% carbon dioxide
 
***Grow in 10% carbon dioxide
 +
***Usually responds to penicillin
 +
**''Actinomyces hordeovulneris''
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***Organism found in seed heads of certain grasses
 +
***Colonies adhere to agar and are non-haemolytic
 +
***Filamentous, branching organisms
 +
***Cause cutaneous and visceral abscessation, pleuritis, peritonitis and arthritis in dogs
  
  
 
===''Actinobaculum suis''===
 
===''Actinobaculum suis''===
 +
 
**Found in preputial mucosa of boars
 
**Found in preputial mucosa of boars
 
**Anaerobic
 
**Anaerobic
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*''Nocardia asteroides'' found in soil
 
*''Nocardia asteroides'' found in soil
 
*Causes granulomatous lesions in animals
 
*Causes granulomatous lesions in animals
 +
*Involved in [[Peritoneal cavity - inflammatory#In dogs|peritonitis]] and [[Bacterial infections#Nocardiosis|pleuritis]] in dogs
 
*Survives and multiplies in macrophages
 
*Survives and multiplies in macrophages
 
*Lesions in thoracic cavity, skin and other tissues
 
*Lesions in thoracic cavity, skin and other tissues
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===''Dermatophilus congolensis''===
 
===''Dermatophilus congolensis''===
 +
 
*Aerobic  
 
*Aerobic  
 
*Motile zoospores
 
*Motile zoospores
 
*No growth on Sabouraud dextrose agar
 
*No growth on Sabouraud dextrose agar
 
*Found in scabs and in foci on skin of carrier animals
 
*Found in scabs and in foci on skin of carrier animals

Revision as of 15:59, 17 February 2008

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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


Arcanobacterium, Actinomyces and Actinobaculum species

  • Non-motile, non-spore-forming bacteria
  • Anaerobic or facultative anaerobes
  • Grow on enriched media; non-acid fast
  • Colonise mucous membranes
  • Modified Ziehl-Neelson negative


Arcanobacterium pyogenes

  • Characteristics:
    • Formerly known as Actinomyces pyogenes and Corynebacterium pyogenes
    • Small facultatively anaerobic rod
    • Grows slowly on blood agar to produce small, white colonies surrounded by a zone of beta-haemolysis after 48 hours
    • Produces hazy haemolysis after 24 hours; pin-point colonies 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; dermonecrotising activity
  • Clinical infections:
    • Suppurative infections
    • Abscesses especially in liver
    • Lymphadenitis, osteomyelitis, peritonitis and neural abscessation
    • Pyometra
    • Endometritis
    • Summer mastitis
    • Ovine foot disease
    • Arthritis
    • Umbilical infections
    • Suppurative pneumonia
  • Treatment:


Actinomyces

  • Usually long filamentous branching Gram positive rods
  • Anaerobic or facultativlyy anaerobic and capnophilic
  • Live in nasopharyngeal and oral mucosa
  • Cause pyogranulomatous lesions
    • Actinomyces bovis
      • Found naturally in oral cavity of cattle
      • Prefers anaerobic conditions but not strict anaerobe
      • Penetrates injured tissues to cause granulomatous inflammation lesions of soft tissues and bone, causing lumpy jaw
      • Usually invades mandible to cause osteomyelitis and may extend to surrounding muscles
      • Organisms found in yellow sulphur granules
      • Club colony formation
      • Colonies adhere to agar media and are non-haemoltic
    • Actinomyces viscosus
      • Commensal of oral cavity of dogs and humans
      • Canine actinomycosis
      • Causes localised subcutaneous pyogranulomatous lesions and fibrovascular proliferation of peritoneal and pleural surfaces in dogs
      • Leads to pyothorax
      • Respiratory distress
      • Cutaneous pustules in horses
      • Abortion in cattle
      • Rods contained in soft grey granules which release the organism when squashed
      • Two types of colonies: large and smooth colonies with V, Y and T configurations or small and rough colonies with short branching filaments
      • Grow in 10% carbon dioxide
      • Usually responds to penicillin
    • Actinomyces hordeovulneris
      • Organism found in seed heads of certain grasses
      • Colonies adhere to agar and are non-haemolytic
      • Filamentous, branching organisms
      • Cause cutaneous and visceral abscessation, pleuritis, peritonitis and arthritis in dogs


Actinobaculum suis

    • Found in preputial mucosa of boars
    • Anaerobic
    • Coryneform morphology
    • Produces urease
    • 3mm diameter colonies with shiny raised centre and dull edge
    • Produces lesions in urinary tract of sows
    • Cystitis and pyelonephritis in sows


Nocardia

  • Aerobic short branching rods
  • Non-motile
  • Spores from aerial filaments
  • Grow on Sabouraud dextrose agar
  • Cell wall contains mycolic acids (hence slightly acid fast)
  • Nocardia asteroides found in soil
  • Causes granulomatous lesions in animals
  • Involved in peritonitis and pleuritis in dogs
  • Survives and multiplies in macrophages
  • Lesions in thoracic cavity, skin and other tissues
  • Chronic, progressive disease
  • Lesions difficult to treat due to resistance of organisms to many antimicrobials (e.g. penicillins)


Dermatophilus congolensis

  • Aerobic
  • Motile zoospores
  • No growth on Sabouraud dextrose agar
  • Found in scabs and in foci on skin of carrier animals
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