M BACTE: COLONY MORPH

• Colony Morphology


  Gives important clues as to the identity of the constituent microorganisms
• Bacteria grow on solid media as colonies


  • A colony is defined as a visible mass of microorganisms all originating from a single mother cell
  • A colony constitutes a clone of bacteria all genetically alike
• Colony Morphology Characteristics


  • Size
  • Colony shape
  • Margin (edge)
  • Elevation
  • Texture
  • Light Transmission
  • Color
• Colony Size


  • Dependent on the type of organism, the growth medium, the number of colonies present on a plate, and culture medium characteristics
  • Colony size usually stabilizes after a day or two of incubation
• Colony Shape


  • Varies
• Colony Margin


  • Varies
• Colony Elevation


  • Colonies can vary in their elevations both between microorganisms and growth conditions, and within individual colonies themselves
• Colony Texture


  • Shiny to dull
  • Smooth to wrinkled
  • Rough
  • Granular
  • Mucoid
• Shiny, smooth, and/or mucoid appearance

  Tends to be associated with the presence of capsular material
• Colony Light Transmission


  • Complete (transparent)
  • Intermediate (translucent)
  • Completely lacking (opaque)
• Colonies can come in a rainbow of colors