Difference between revisions of "Fusobacterium necrophorum"

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*[[Bones Inflammatory - Pathology#Osteitis|Osteitis]]
 
*[[Bones Inflammatory - Pathology#Osteitis|Osteitis]]
 
[[Contagious Footrot]]
 
[[Contagious Footrot]]
 
+
[[Necrobacillosis]]
  
 
[[Category:Cattle]][[Category:Pig]][[Category:Horse]][[Category:Sheep]]
 
[[Category:Cattle]][[Category:Pig]][[Category:Horse]][[Category:Sheep]]
 
[[Category:Pathogenic anaerobic non-spore-forming Gram-negative ]]
 
[[Category:Pathogenic anaerobic non-spore-forming Gram-negative ]]
 
[[Category:To_Do_-_Bacteria]]
 
[[Category:To_Do_-_Bacteria]]

Revision as of 11:18, 30 June 2010

  • Characteristics:
    • Normal inhabitant of mammalian gut; cannot invade normal tissue
    • Pleimorphic - long and filamentous or short cocci
    • Fermentative
    • Haemolytic on blood agar
    • Grey, round, shiny colonies
    • Three biotypes: biotype A has greatest haemolytic activity and virulence
  • Pathogenesis and pathogenicity:
    • Primary pathogen in various diseases of farm animals
    • Mixed bacterial infections
    • Can be secondary to IBR
    • Extracellular haemolysin contributes to infection
    • Heat-stable leucocidin - correlated with biotype and virulence
    • Cytoplasmic toxin - haemolytic
    • LPS endotoxin causes host damage
    • Antibodiy levels rise with age, suggesting that these are not protective
  • Calf diphtheria/necrotic laryngitis in cattle:
    • Necrobacillosis of mouth and pharynx of young calves
    • Pharyngitis and laryngitis
    • Associated with bucket feeding where buckets are contaminated with faeces
    • Bacteria enter through abrasions in the mucosa of the pharynx and larynx
    • Fever, depression, anorexia, salivation, respiratory distress and halitosis
    • Aspiration of necrotic material into lungs may cause fatal bronchopneumonia
    • Treatment: potentiated sulphonamides or tetracyclines
  • Bovine liver abscesses:
    • Sudden change in diet to a high grain diet causes ruminal acidosis and rumenitis
    • Ulceration of rumenal mucosa and colonisation by F. necrophorum and Arcanobacter pyogenes
    • Emboli carry organisms to the liver via the portal vein
    • Focal necrosis and abscess formation in liver
    • Putrid smell
    • Rarely show clinical signs
    • Management important
  • Necrotic rhinitis of pigs:
    • Sporadic condition in young pigs
    • Suppuration and necrosis of snout
    • F. necrophorum and other organisms enter through abrasions in snout mucosa
    • Facial swelling, sneezing, putri nasal discharge
    • Chronic infection - faical deformity
    • Treat with potentiated sulphonamides
    • Occasional pharyngitis/laryngitis in pigs
  • Thrush of the hoof:
    • Necrosis of horse hoof associated with poor hygiene, wet conditions
    • F. necrophorum secondary to hoof damage causes localised inflammatory response
    • Thrush especially of hind feet, with putrid discharge in sulci
    • Provide dry, clean bedding
  • Black spot of bovine teats
    • Localised necrosis and scab formation of teat orifice and sphincter of dairy cows due to F. necrophorum
    • May predispose to mastitis
  • Necrotic wound infections often in association with facultative anaerobes
  • Interdigital dermatitis (pododermatitis) in sheep in association with D. nodosus and Arcanobacter pyogenes, predisposing to footrot
  • Causes laryngeal chondritis in sheep
  • Mixed infections in heel abscesses in sheep
  • Mixed infections in pyothorax
  • Mixed infections in aspiration pneumonia and in bovine traumatic reticuloperitonitis and pericarditis
  • Involved in subcutaneous abscesses due to cat bites
  • May be involved in chronic fibronecrotic rhinitis
  • Osteitis

Contagious Footrot Necrobacillosis