Download - Culture Medias
Culture MediaCulture Media
ByBy
Zahoor AhmedZahoor AhmedB.S MLT 06B.S MLT 06
DefinitionsDefinitions MediumMedium Any preparation that contains nutrients Any preparation that contains nutrients
essential for bacterial growth.essential for bacterial growth.
Culture medium:Culture medium: A nutrient substance (solid or liquid) A nutrient substance (solid or liquid)
that is used to grow micro-organismsthat is used to grow micro-organisms..
Inoculation of mediaInoculation of media Introduction of infected material to the Introduction of infected material to the
mediummedium
for cultivation of organisms.for cultivation of organisms.
ClassificationClassification
Classified on the following basis.Classified on the following basis.
a)a) Consistency Consistency
b)b) Nutritional Nutritional
c)c) Functional Functional
ConsistencyConsistency
Sub-divided into Sub-divided into
a )a ) Solid Solid e.ge.g nutrient agar nutrient agar
b )b ) Semi-solidSemi-solid e.g e.g peptone water. peptone water.
c )c ) Liquid mediumLiquid medium e.g e.g nutritional nutritional broth.broth.
NutritionalNutritional
Further sub-divided intoFurther sub-divided into
a )a ) SimpleSimple e.ge.g peptone water peptone water
b )b ) ComplexComplex e.ge.g blood agar blood agar
c )c ) SyntheticSynthetic e.ge.g Davis /mingioli Davis /mingioli mediummedium
FunctionalFunctional
Further sub-divided intoFurther sub-divided into
a )a ) Basic media Basic mediab)b) Enriched media Enriched mediac )c ) Selective media Selective mediad )d ) Indicator media Indicator mediae )e ) Transport media Transport mediaf )f ) Identification media Identification media
Basic MediaBasic Media These are simple media contains only These are simple media contains only
basic substances i.e Co2 ,N , &minerals.basic substances i.e Co2 ,N , &minerals. Support those organisms that don't Support those organisms that don't
require special nutrient.require special nutrient. Often used in the preparation of Often used in the preparation of
enriched media.enriched media. Also used for sub culturing of Also used for sub culturing of
pathogens.pathogens. Examples:Examples: Nutrient agarNutrient agar & & Nutrient broth.Nutrient broth.
Enriched MediaEnriched Media
Used for the organisms that require Used for the organisms that require exact growth requirements.exact growth requirements.
Basic media may be enriched with Basic media may be enriched with whole or lyzed blood , serum , whole or lyzed blood , serum , peptones , vitamins etc.peptones , vitamins etc.
Increases the no: of pathogens Increases the no: of pathogens because it fulfill the whole because it fulfill the whole nutritional requirements.nutritional requirements.
Examples:Examples: BloodBlood & & chocolate agarchocolate agar..
Selective MediaSelective Media
These are solid media contains These are solid media contains substances substances i.ei.e bile salts ,dyes etc. bile salts ,dyes etc.
Inhibit the growth of one Inhibit the growth of one organism to allow the other one organism to allow the other one i.ei.e inhibit the growth of normal inhibit the growth of normal flora and allow the growth of flora and allow the growth of pathogen.pathogen.
Contin…..Contin…..
Examples:Examples:
MacConkey agarMacConkey agar for for Gram-Gram-negativenegative bacteria bacteria
Low stein Jensen's agarLow stein Jensen's agar for for M . M . bacterium.bacterium.
TCBSTCBS for for vibrio.vibrio.
Indicator MediaIndicator Media Also called differential media.Also called differential media.
Used to differentiate one organisms Used to differentiate one organisms from another from another
organisms.organisms.
Dyes , indicator or other substances are Dyes , indicator or other substances are added to differentiated organisms added to differentiated organisms i.e i.e
Neutral red , phenol red , eosin , or Neutral red , phenol red , eosin , or methylene blue.methylene blue.
Contin……Contin……
ExamplesExamples
a)a) EEosin methylene blue (EMB),osin methylene blue (EMB), which is differential for lactose and which is differential for lactose and sucrose fermentationsucrose fermentation
b)b) MacConkey (MCK),MacConkey (MCK), which is which is differential for lactose fermentation differential for lactose fermentation
c)c) MMannitol salt agar (MSA),annitol salt agar (MSA), which is which is differential for mannitol fermentation differential for mannitol fermentation
Transport MediaTransport Media
These are semi-solid media.These are semi-solid media. Used for the temporary storage of Used for the temporary storage of
specimens.specimens. Maintain the viability of all organisms Maintain the viability of all organisms
in the specimen.in the specimen. Transport media typically contain only Transport media typically contain only
buffers and salt .buffers and salt . The lack of carbon, nitrogen, and The lack of carbon, nitrogen, and
organic growth factors prevents organic growth factors prevents microbial multiplicationmicrobial multiplication..
Contin……Contin…… Ensure the survival of aerobic and Ensure the survival of aerobic and
anaerobic organisms.anaerobic organisms.
Examples:Examples:
a)a) Thioglycollate brothThioglycollate broth for for strict strict anaerobesanaerobes . .
b)b) Cary-blair mediumCary-blair medium for for enteric enteric pathogen.pathogen.
c)c) Amies mediumAmies medium for for gonococci.gonococci.
Identification MediaIdentification Media
Help to identify bacteria isolated on Help to identify bacteria isolated on primary growth.primary growth.
Organisms are identified by Organisms are identified by changing medium color or producing changing medium color or producing gas.gas.
Organisms used to inoculate Organisms used to inoculate identification media must be first identification media must be first isolated in pure culture.isolated in pure culture.
Contin….Contin….
Examples:Examples:
Peptone waterPeptone water Urea brothUrea broth Klinger iron agar.Klinger iron agar.
PreparationPreparation Wash hands & wear glovesWash hands & wear gloves
Sterilize all equipmentsSterilize all equipments
Pour D/W in glassware (required amount)Pour D/W in glassware (required amount)
Add powder ingredients (required amount)Add powder ingredients (required amount)
Heat to dissolve completelyHeat to dissolve completely
AutoclaveAutoclave
Dispense the medium into tubes ,bottles Dispense the medium into tubes ,bottles &plates&plates
Store at required temperatureStore at required temperature
Sterilizing Culture Sterilizing Culture MediaMedia
Autoclaving:Autoclaving: To remove bacterial endospores as To remove bacterial endospores as
well as well as vegetative cells.vegetative cells. Steaming at 100 c:Steaming at 100 c: used to sterilize media containing used to sterilize media containing
ingredients that would be broken ingredients that would be broken down or inactivated above 100 c.down or inactivated above 100 c.
Filtration:Filtration: Removing bacteria from fluidsRemoving bacteria from fluids..
Storage of Culture MediaStorage of Culture Media
Nutrient broth and agar can be Nutrient broth and agar can be stored for 6 months at 12-l6°C. stored for 6 months at 12-l6°C.
Agar plates should be stored at 2-Agar plates should be stored at 2-8°C in sealed containers to avoid 8°C in sealed containers to avoid loss of moisture.loss of moisture.
It is important to store all media It is important to store all media away from light.away from light.
DO NOT FREEZE.DO NOT FREEZE.
Q.C of Culture MediaQ.C of Culture Media
PH values.PH values. TemperatureTemperature SterilitySterility Growth performanceGrowth performance StabilityStability