Pseudomonas & Burkholdera

• Pseudomonas and Burkholderia

  • Gram-negative, medium-sized rods
  • Motile (except B. mallei) by means of polar flagella
  • Obligate aerobes
  • Non-spore-forming
  • Capsule is sometimes present
  • Catalase and Oxidase-positive
• Sources/Reservoir of Pseudomonas aeruginosa

  • Environmental organisms and saprophytes - commonly found in aquatic habitat and in soil
  • Can also be found as normal flora on the skin, mucous membranes and in the intestine (feces)
• Burkholderia mallei


  Specialized mammalian parasite
• Burkholderia pseudomallei and Pseudomonas aeruginosa


  Occasional parasites of animals
• Virulence Factors of P. aeruginosa

  • Pili/Fimbriae
  • Capsules
  • Exotoxin A
  • Phospholipase C
  • Protease
  • Elastase
  • Pyocin
  • Siderophores (Pyochelin and Pyoverdin)
  • Exoenzyme S
  • Extracellular slime
  • Outer membrane LPS
• Virulence Factors of P. pseudomallei

  • Exotoxin
  • Dermonecrotic protease
  • Lecithinase
• Growth media

  • Sheep blood agar
  • MacConkey Agar
  • Trypticase soy agar
• Growth of P. mallei

  Enhanced by 1% glycerol
• P. aeruginosa

  Will also grow on many of the selective media for the Enterobacteriaceae
• Colony Morphology Pseudomonas aeruginosa

  • Colonies are large, flat, greyish-blue with a characteristic fruity, grape-like odor (aminoacetophenone)
  • Colonial variations: S-forms (soft and shiny) R-forms (dull and granular) M-forms (mucoid)
  • Most strains give a clear zone of hemolysis on blood agar
  • Some strains have colonies with distinctive metallic sheen
  • Large, pale colonies on MCC with greenish-blue pigment
  • Medium, red colonies on BG and XLD (no H2S)
  • P. aeruginosa may be distinguished from other species by its ability to grow at 42°C.
• Pigments

  • Pyocyanin - blue-green pigment; unique to P. aeruginosa
  • Pyoverdin - yellow-green pigment; also known as fluorescein (fluoresce under UV light)
  • Pyorubin - red pigment; less common
  • Pyomelanin - dark brown; less common
• Colony Morphology Pseudomonas pseudomallei (now: Burkholderia pseudomallei)


  • Colonial growth varies from smooth and mucoid to rough with a dull, wrinkled, corrugated surface
  • In the smooth form the colonies are round, low-convex, entire, shiny and greyish-yellow
  • After several days, the colonies become opaque, yellowish-brown and umbonate
  • The growth has a characteristic earthy or musty odor
  • Partial and later, complete hemolysis occurs on sheep blood agar
  • Grows on MacConkey agar, utilizing lactose, but there is no growth on deoxycholate or Salmonella-Shigella (SS) agars
• Colony Morphology Pseudomonas mallei (now: Burkholderia mallei)


  • Non-hemolytic, growth is slower than that of P. aeruginosa and P. pseudomallei but in 24-48 hours the colonies are 1-2 mm in diameter, smooth and white to cream
  • As they age, they become granular and yellowish or brown in color
  • P. mallei is unable to grow on MacConkey Agar
  • Can be easily cultured on agar enriched with glycerol or on selective medium
• Mallein test


  A glycoprotein analogous to tuberculin extracted from Pseudomonas mallei, it is non-toxic for healthy animals
• Subcutaneous test


  SC inoculation of mallein results in swelling at the injection site and fever
• Ophthalmic test


  Instillation of mallein into the conjunctival reaction in the cols obses test, infammatory and purient
• Intrapalpebral test


  SC inoculation of a small amount of mallein into the skin of the lower eyelid gives localized, edematous swelling and purulent conjunctivitis
• Pseudomonas mallei

  Glanders

  Equine
• Pseudomonas mallei

  Glanders treatment

  Sulfonamide and Tetracycline
• Pseudomonas pseudomallei

  Melioidia (Pseudoglanders)

  Animals
• Pseudomonas pseudomallei

  Melioidia Treatment

  Combination of Novobiocine and Tetracycline