Culture Media Know-hows

• What is a culture media?


  • It is any medium that contians all what is needed to support bacterial growth.
  • The Agar used in media prep is derived from red algae
  • Solidifies at 40-50 degC
  • Melts at 80-90 degC
  • Cooling temp at 55-60 degC
  • Commercially standard amount usually plated is 20-25mL
• Tubed Media

  • Weigh, Dissolve, Dispense, Autoclave
  • We Dissolve using a "beaker"


  Plated Media

  • Weigh, Dissolve, Autoclave, Dispense
  • We Dissolve using "Erlenmeyer Flask"
• Types of Culture?

  1. Pure Culture = media that contains only 1 species of bacteria growing on it
  2. Mixed Culture = media that contains more than 1 species of bacteria growing on it
  3. Stock Culture = cultures that is predominantly used in quality control
  4. ATCC = American Type Culture Collection
• What is the best way to obtain a pure culture?


  Streak Plate Method
• Different Kinds of Transport Media

  1. JEMBEC and Transgrow = Neisseria spp
  2. Amie's = Respiratory specimens
  3. Stuart's = Viral Transport Media
  4. Todd Hewitt and Lim Broth = Streptococcus agalactiae
  5. Cary-Blair = Stool samples
• Some of the Selective Agars and their Respective bacteria

  Middlebrook = Mycobacteria spp

  CBTA = Corynebacterium diptheriae

  BCYE = Legionella spp

  Regan-Lowe = Bordetella pertussis

  TCBS = Vibrio spp

  EMB = for Enterobacteriaceae

  MAC = for Gram negative bacteria

  PEA = for Gram positive bacteria

  CIN = Yersinia enterocolitica

  
  

  Anaerobic Media

  • Thioglycollate = almost all bacteria; for general use
  • Pre-reduced, anaerobically sterilized (PRAS) Agar
  • CDC-A = Prevotella, Porphyromonas, and the Bacteroides fragilis group
  • BBE "Bacteroides Bile Esculin" = for Bacteroides fragilis group
• What is the use of the tap water agar?


  used to differentiate aerobic actinomycetes such as Nocardia, Rhodococcus, Tsukamurella, Streptomyces, Actinomadura, Gordonia which are known to be "fungus-like" bacteria
• Plates for semiquantitation: Streak in 4 quadrants; this is called "isolation streaking".

  • Isolation Streaking: Involves successive dilution of the organism until you have the cells at low density.
  • Flame inoculating loop: Done in between streaks to avoid over-inoculation.
  • Growth: Heavy/many (4+), moderate (3+), few or light (2+), rare (1+).
  • Plate count: Most common method to measure growth; measures the number of viable cells in milk, food, water, and soil (CFU/mL).