micro

• Complex growth media

  exact composition is unknown
• Synthetic growth media

  defined chemical composition
• General Purpose growth medium

  can grow variety of bacteria
• Selective growth media

  allows some types of grow, while inhibiting others
• Differential growth medium

  different types of bacteria will have different characteristics
• Mannitol Salt Agar

  • differential and selective
  • ferment mannitol
• Mannitol Salt Agar

  • differential and selective
  • ferment mannitol
  • acidic byproducts that turn phenol red into yellow
  • yellow halo colony
• Eosin Methylene Blue

  • differential and selective
  • ferment lactose
  • sugar
  • produce acid that produces green colony
• TSA agar

  • general purpose growth
  • non differential
• Endospore Staining

  1. Apply malachite green (primary stain)
  2. apply heat (mordant)
  3. apply water (decolorizer)
  4. apply safranin red (counter stain)
• Air Sampling

  • 300 CFU/ml limit on air microbes
  • immunocompromised <100 CFU/ml
  • # of colonies / time x volume of plate (K 35.5)
• Optimum temperature

  growth is at maximum
• Obligate aerobes

  requires O2
• Microaerophiles

  can use O2 when it is present at reduced levels

  stacked one inch before the top
• Facultative aerobes

  may grow in the absence of O2, does not affect its metabolism

  bacteria grouped at the top, also have some at the body
• Obligate Anaerobes

  killed in the presence of O2
• Aerotolerant anaerobes

  • tolerates O2 and can grow in its presence, unable to do cellular respiration
  • all over the tube