CULTURE MEDIA

• What are the three classifications of culture media based on physical state?


  Liquid, semisolid, and solid
• What are the two types of solid culture media based on liquefaction?


  Liquefiable and non-liquefiable
• What is an example of a non-liquefiable solid medium?


  Chopped meat
• What are the two main types of culture media based on composition?


  Synthetic

  non-synthetic

  Tissue
• What is the natural habitat of Shigella?


  The intestinal tracts of humans and other primates
• What is the purpose of sterilizing culture media at 121°C for 15 minutes?


  To eliminate any microbial contamination
• What are the functions and uses of different types of culture media?

  • Simple/Basal/Supportive/General media: For general growth
  • Enriched media: Supports growth of fastidious organisms (e.g., BAP)
  • Enrichment media: Ex. Selenite
  • Selective media: Inhibits certain bacteria to isolate others (e.g., PEA for Gram-positive)
  • Differential media: Distinguishes between different types of bacteria based on growth characteristics
• What is the function of phenylethyl alcohol in culture media?


  It inhibits the growth of Gram-negative bacteria
• What is the purpose of using a pH indicator in selective media?

  To indicate the pH changes due to bacterial growth
• What type of bacteria does PEA inhibit?


  Gram-negative bacteria
• What is the significance of using selective media in microbiology?

  It allows for the isolation of specific types of bacteria
• What is the pH range for Vibrio species growth in selective media?

  8-10
• What is the role of inhibitors in selective media?

  To suppress the growth of unwanted bacteria
• How does selective media differ from differential media?

  Selective media inhibits certain bacteria, while differential media distinguishes between types
• Contains 0% Agar and does not contain any solidifying agent


  Liquid Medium
• Examples of Liquid Medium

  • TSB
  • BHI
  • Thioglycolate
• Contains 0.5-1% Agar, Ex. SIM


  Semisolid Medium
• Types of Solid Media

  • Liquefiable
  • Non-liquefiable
• Contains 2-3% Agar


  Liquefiable
• Examples of Liquefiable Solid Media

  • TSIA
  • MAC
  • BAP
  • CAP
  • Plate media
• Example of Non-liquefiable Solid Media

  • Chopped meat - for anaerobic bacteria
  • Rice grain - for fungi
• Isolated from rice grain


  Microsporum canis
• Culture media according to the composition

  • Synthetic
  • Non-synthetic
  • Tissue
• Chemically define medium where all the components are known to the user. ex. 2.4g of glucose and 1.0g of protein


  Synthetic
• Complex medium that is composed of some unknown substances (Peptones, Meat, Yeast extract)


  Non-synthetic
• Example of non-synthetic composition

  • NB
  • TSB
  • MAC
  • BAP
• Cell free media chocolate agar


  Tissue
• Example of tissue composition medium

  • McCoy Cells
  • Vero cells
  • A549 cells
  • HeLa cells
  • Hep 2 cell
• Mouse cell line for the isolation of Chlamydia trachomatis


  McCoy cells
• African green monkey kidney cells


  Vero cells
• Lung carcinoma


  A549
• Cervical cancer


  HeLa cells
• Laryngeal cells/cancer


  Hep 2 cell
• Two types of dispensing

  • Plated
  • Tubed
• Steps in Plated

  1. Weigh
  2. Dissolve
  3. Sterilize
  4. Dispense
• Computation for weigh Ex. 24g in 100 mL


  $24g*$$100ml =$$2400/1000=$$2.4g in 100mL$
• Example of dissolve 


  Half plate of clear powder
• Example of sterilize


  121 degrees Celsius for 15 mins.
• Steps for Tubed

  1. Weigh
  2. Dissolve
  3. Dispense
  4. Sterilize
• For non-fastidious organisms with no special requirements for growth


  Simple/Basal/Supportive/General isolation/General purpose media