Arcanobacter 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


Treatment

  • Penicillin or broad spectrum antibiotics