Erysipelothrix rhusiopathiae


  • Causes erysipelas in pigs and turkeys worldwide
  • Arthritis and discospondylitis in pigs as well as cutaneous lesions
  • Occasionally causes arthritis in sheep and disease in other animals
  • Causes erysipeloid, a localised cellulitis in humans
  • Found in porcine tonsils - 50% of pigs are thought to be carriers
  • Bacteria excreted in faeces and oronasal secretions
  • Survive in soil for less than 35 days
  • Present on fish


  • Gram-positive, small rod (smooth form) or filamentous (rough form)
  • Facultative anaerobe
  • Non-motile
  • Catalase negative, oxidase negative, coagulase positive
  • Grow on nutrient agar; growth enhanced by addition of blood or serum
  • Small colonies with incomplete haemolysis in 48 hours
  • Hydrogen sulphide formed as black central line in TSI agar
  • Growth over wide rangs of temperatures and pH

Identification and diagnosis

  • Isolates from acute infections produce smooth colonies; 1.5mm diamteter, convex and circular with even edges
  • Isolates from chronic infections produce rough colonies; larger, flat and opaque colonieswith irregular edges
  • Biochemical tests
  • Serotypying according to a heat-stable peptidoglycan extracted from the cell wall
  • Virulence testing in lab animals
  • PCR for detection of virulent isolates

Pathogenesis and pathogenicity

  • Route of infection: ingestion from pig faeces
  • Entry via tonsils, skin or mucous membranes
  • Capsule prevents phagocytosis
  • Adhere to endothelial cells
  • Produce neurominidase which enhances cell penetration
  • Septicaemia with vascular damage
  • Swelling of endothelial cells, monocyte adherence to vascular walls and hyaline microthrombus formation
  • Bacteria localise in synovia of joints and on heart valves during bacteraemia and cause chronic lesions
  • Host immune response to persistent bacterial antigens causes long-term damage to the joints

Swine Erysipelas

Turkey erysipelas

Sheep infections

  • Non-suppurative polyarthritis of lambs from contamination of navel or tail-docking/castration wounds
  • Cellulitis and laminitis in older lambs and ewes causing post-dipping lameness - entry through skin abrasions in hoof from contaminated dip
  • Valvular endocarditis and pneumonia in ewes reported
    • Clinical sighns:
      • Cutaneous erysipelas
      • Polyarthritis in lambs
      • Rarely fatal septicaemia
    • Enters via:
      • Cuts, abrasions
      • Castration or docking wounds
      • Haematogenous spread -> subacute or chronic fibrinopurulent polyarthritis
    • Morbidity up tp 50%
    • Affects mostly unthrifty lmbs
    • Fibrosis and osteophyte formation in later stages -> persistent lameness

Human erysipeloid

  • Infection through skin wounds from fish and poultry
  • Localised cellulitis
  • Occasional joint and heart disease after haematogenous spread if untreated