Micro

• Erysipelothrix


  Genus containing two species
• Species in Erysipelothrix genus

  • Erysipelothrix rhusiopathiae
  • Erysipelothrix tonsillarum

  
• Erysipelothrix rhusiopathiae


  • Important pathogen of swine and poultry

  
• Erysipelothrix tonsillarum


  • Associated with endocarditis in dogs
• Unspecified event


  1995
• Erysipelothrix rhusiopathiae was previously called E. insidiosa
• Erysipelothrix


  • Small, non-motile, Gram-positive rods
  • Non-spore forming
  • Catalase negative
  • Oxidase negative
  • Mesophilic
  • Facultative anaerobe
  • Fermentative

  
• Figure 13.7 shows Erysipelothrix rhusiopathiae in a Gram-stained smear, with small Gram-positive rods and some short filaments indicating the colonies are changing to the rough form

  
• Erysipelothrix rhusiopathiae was discovered by Loffler in 1886 and found on mucous membranes of normal swine, sheep, turkey, ducks and rodents, as well as in the slime on the bodies of fresh and saltwater fish and crustaceans

  
• Carrier pigs are the main reservoir of Erysipelothrix rhusiopathiae, even though it can live in soil for several weeks
• Mode of infection and transmission

  1. Worldwide distribution

  2. Acquired by direct contact with infected pigs and fomites

  3. Transmitted by ingestion, including in fish meal

  4. Disease appears after abrupt change in diet or sudden weather change in temperate zones
• Virulence factors of Erysipelothrix

  • Hyaluronidase
  • Coagulase
  • Neuraminidase

  
• No toxins are demonstrated for Erysipelothrix
• Erysipelothrix invades skin and bloodstream
• Clinical manifestations of Erysipelothrix rhusiopathiae infection in domestic animals

  • Acute (septicaemic) form
  • Skin (urticarial) form
  • Chronic (arthritic and cardiac) form

  
• Acute/septicaemic form


  • High fever
  • Breathing difficulty due to lung edema
  • Dark red mucous membranes
  • Short course and high mortality
• Skin/urticarial form


  • Reddish or purple diamond-shaped patches
  • Scabs and skin sloughing
• Cardiac form


  • Endocarditis with cauliflower-like growths on heart valves
• Arthritic form


  • Fibrosis in joints
• Erysipelothrix infection in sheep and calves

  • Focal cutaneous infection around hooves
  • Polyarthritis and lameness
  • Entry via abrasions, unhealed navel, and wounds
• Erysipelothrix infection in fowl


  • Septicemia
• Erysipelothrix infection in dogs

  • Valvular endocarditis
• Erysipelothrix infection in marine mammals

  • Fatal infections in dolphins and sea lions
• Specimens for diagnosis


  • Blood and viscera in acute/septicemic form
  • Affected tissues (heart, skin, joint fluid) in chronic form
• Isolation and cultivation


  1. On blood agar in 5-10% CO2

  2. Two colony types: small, round and smooth; rough, large with irregular edges (frequently from chronic infections)

  3. Alpha-greenish hemolysis around colonies

  
• hoof


  Lesions appear in this area
• poly arthritis


  Affects more than one joint
• How the bacteria infect the animal

  1. Through abrasions and cracks in the skin

  2. Through unhealed wounds or lesions
• septicemic form


  Affects birds
• valvular endocarditis


  Inflammation of the inner lining of the heart chambers and valves, affects dogs
• For marine animals like dolphins and sea lions, infection with this bacteria is fatal
• Specimens collected to detect the bacteria

  • Blood and viscera from acute or septicemic form
  • Affected tissues; heart, skin, joint fluid in chronic form

  
• Specimen collection depends on the form of infection

  1. For acute or septicemic form, collect from blood or internal organs

  2. For chronic form, collect from affected organs like heart, skin, joint fluid
• Colonies on blood agar

  • Small, round and smooth (from acute form)
  • Rough, large with irregular edges (from chronic infections)
• Hemolysis around young colonies

  • Alpha-greenish hemolysis
• Gram stain of colonies

  • Smooth colonies - slender gram-positive rods resembling Listeria

  Rough colonies - highly pleomorphic and filamentous forms
• Identification


  • Non-motile, catalase negative, coagulase positive

  Produces H2S in TSI agar, differentiates from Listeria

  
• Antigenic nature


  3 somatic antigen groups (A,B,N)

  22 serotypes based on peptidoglycan differences
• Resistance


  • Survives at room temperature for months, in moisture for years

  Resists boiling for 2 hours in thick pork meat

  Phenolic compounds are not effective
• Immunity


  Humoral and hypersensitivity reactions

  Live attenuated vaccines used in pigs and turkeys