Culture media can be classified based on consistency, constituents, and requirements. There are solid, liquid, and semi-solid media. Media can also be simple, complex, or synthetic based on constituents. Different types of media are used for various purposes like enrichment, selection, indication, differentiation, and transport. Examples provided include nutrient agar and broth as simple solid and liquid media. Blood agar and chocolate agar are enriched solid media used to culture bacteria like streptococcus pneumoniae and haemophilus influenzae. Thiosulfate citrate bile salts sucrose agar and MacConkey agar are selective and differential solid media. Transport media include Stuart medium and Carey Blair medium.

1. Culture Media
 Types [Classification]
 Uses [Application]
- J. Aditya
- Roll number 50

2. Learning
Objectives
The student learning about this must obtain the
following knowledge of :-
• Classification of culture media on the basis of
various factors and subtype examples
• The applications of these with examples of
each

3. Classification :
BASIS
Consistency
Constituents
Requirement
Consistency
Solid Liquid Semi-solid
Solid media Distinct colony Morphology
Agar [Nutrient, Blood or Chocolate]
Liquid Bulk Preparation Peptone water, BHIB ,
Nutrient broth
Semi-solid To demonstrate Bacterial motility Low conc
Agar [0.5 to 1%]

4. Constituents
Simple Complex Synthetic
Simple Media : Also known as basal media its examples
are nutrient broth and nutrient agar
Nutrient Broth : Peptone + NaCl + water + Meat extract
Nutrient Agar : 2% agar + Nutrient Broth
Complex Media : Addition of special ingredients
Synthetic : Pure chemical substances

5.  Enriched Media : Basal medium + Nutritional element like blood ,
serum or eggs
 Enrichment Media : For suppression of commensal growth of
bacteria while pathogen can grow
 Selective Media : Just like enrichment media but over addition of
inhibitors to solid media
 Indicator Media : An indicator is added to the medium so that
when the organism grows on it, colour will change.
 Differential Media : It is a type of Indicator medium but for
identifying closely associated bacteria
 Transport Media: For specimen transport
 Anaerobic Media : Medium contains reducing agent chemicals
Requirement

6. Examples and uses of Culture Media
 Solid, Enriched, Differential culture media
 Contains Agar + Peptone + Blood [from
cow/pig/horse]
 Supports Aerobes, anaerobes and fungi [all
except Haemophilus ]
 Most commonly used for : Streptococcus
pneumoniae
 Solid, Enriched culture media
 Made by adding sheep blood to nutrient agar [on
heating releases factor X ,V and haemoglobin ]
 Used for organisms like Haemophilus influenzae,
Neisseria gonorrhoeae, Pneumococcus etc.
 Addition of antibiotics[vanomycin, colistin and
nyastatin] makes it Thayer-Martin medium which is a
selective media.

7.  Brain-heart infusion broth is a Liquid,
Enriched culture media
 Prepared from non enzymatic infusion
of calf brain and cow heart often with
dextrose and peptone
 Used for fastidious microbes
Tetrathionate is Liquid , Enrichment
media that inhibits growth of
coliforms while groth of typhoid-
paratyphoid bacilli takes place
Selenite F broth is also Liquid ,
Enrichment media and is used in
case of dysentery for isolation of
Salmonella.

8.  Thiosulphate citrate bile salt sucrose agar
(TCBS) is a Solid, Selective , Indicator media
 It is used specifically for Vibrio growth [due
to alkaline pH] in case of suspected Cholera.
It inhibits other gut flora.
 Deoxycholate citrate agar on other hand is
Solid, Selective media used for Salmonella
and Shingella
 Wilson-Blair media is Solid, Selective, Indicator media used
specifically for Salmonella typhi
 S.typhi reduces sulphite content to sulphide giving a black metallic
sheen on the colony.
 McLeod’s medium is Solid, Selective, Indicator medium used for
Corynebacterium diptheriae . Reduction of potassium tellurite to
tellurium takes place producing black colonies.
Indicator Media

9. Wilson Blair medium
CLED medium
MacConkey medium

10.  MacConkey medium is a Solid, Complex, Differential medium
consisting of peptone + taurocholate + lactose + neutral red +
agar
 It gives pink colour to colonies of lactose fermenters like E.coli
and Klebsiella
 The colonies remain colourless in case of Salmonella or
Shingella
 Cysteine lactose electrolyte deficient (CLED) agar is Solid,
Differential media used for urine pathogens
Transport Media
Stuart medium for gonococci and enteric bacilli [Synthetic, Semi-
solid, Anaerobic medium which contains reducing agents like
sodium thioglycolate]
Carey Blair medium is also used for enteric pathogens.

11. Robertson’s medium is also called cooked
meat medium contains yeast extract ,
dextrose, haemin and vit. K alongwith pieces
of meat.
Thioglycolate medium is first boiled for
removal of oxygen so that anaerobic microbes
may grow in it at the bottom. pH is around 7.2
Cooked
Meal
medium
Thioglycolate .

12. Find out Yourselves
• Hank’s balanced salt solution
• Todd-Hewitt broth
• Lowenstien-Jensen medium
• Mannitol salt agar
Note : Blood agar contains blood, Brain-heart infusion broth contains both
brain and heart but Chocolate agar doesn’t contain chocolate.
Enriched media and Enrichment media are not the same in classification.

13. Thank you