Bacterial Culture Flashcards
What is a culture medium?
A water solution of various nutrients that encourage the growth or organisms
What does a culture medium generally contain?
3
Energy
Carbon, nitrogen and other essential nutrients
Growth factors (may be added to encourage the growth of a particular fastidious organism)
What two forms can culture medias come in?
Liquids or gels
What does the success of culture depend on?
Selection of appropriate culture media
What are the five different types of medias?
General purpose media
Enriched media
Selective media
Differential media
Selective and differential media
Give an example of a general purpose media.
Horse blood agar
How is horse blood agar a general purpose media?
It supports the growth of most gram-positive and gram-negative bacteria
What is horse blood agar made from?
Proteins sources
Sodium chloride
5% blood
What is enriched media?
Media fortified with yeast extracts or protein infusions, useful in growing fastidious organisms
What are enriched medias fortified with?
Yeast extracts
OR
Protein infusions
Give an example of an enriched media.
Chocolate agar
What is present in chocolate agar?
Red blood cells that have been lysed
Name two fastidious organisms that require chocolate agar.
Neisseria meningitis
Haemophilus influenzae
What are selective medias?
Selective medias encourage the growth of one organism whilst suppressing the growth of another
Give an example of a selective media.
MacConkey agar