Culture media Definition :- 1-Synthetic media : 2-Routine culture media: Routine culture media
Post on 24-Feb-2016
145 Views
Preview:
DESCRIPTION
Transcript
Culture mediaDefinition :-1-Synthetic media :2-Routine culture media:
Routine culture mediaCommon ingredients :-Dehydrated powdersBacteriological quality
Peptone :-Nitrogen amino acidsAnimal & plant proteins
[lean meat - soya bean]Proteolytic enzymes : Trypsin
Meat extract :- [Lab. Lemco]Carbon Vitamins Mineral saltEvaporation of lean meat
Mineral salts :-Sulphates Phosphates Sod.chlorideEnzymes activityIsotonic
Water :-
Agar :-Complex inert long chain polysaccharideSea weedsNew Zealand JapanMelting temp. : 90⁰c - 95 ⁰cSolidifying temp. : 39 ⁰c - 42 ⁰cConcentration in media : 1.2 - 2% [solid]
0.4 - 0.5 [semi solid]
Three forms according to the consistency :-1-Solid :-Agar 1.2 up to 2%Plates or bottlesIsolation from specimens2-Semi – solid :-Agar < 1% [0.4 - 0.5%]Bottles & tubesMotilitySome biochemical reactionsPreservationTransport media3- Fluid / Broth :-Blood culture bottlesEnrichment mediaSome biochemical reactions[ Carbohydrates fermentation ]
Types of routine culture media :- 1- Basic or simple media :
Definition :Nutrient agar nutrient brothNon-fastidious organismsstaphylococci E.coli
2- Enriched media :Definition :Blood agar Chocolate blood agarFastidious organismsStreptococcus pyogenes Niesseria
3- Differential media : Definition : Fermentaion : indicator media MacConkey agar : lactose & non-lactose fermenters
Haemolysis :Blood agarα- and β hamolysis
4- Selective media :Definition :
1) Adding substances2) Changing the PH
Dyes : Crystal violetblood agar [S.pyogenes] Malachite green L.J [Mycobacteria]
Bile salts :Sodium deoxycholate [DCA]Salmonella & Shigella
Mineral salts :Sod.chloride [6.5%]Mannitol salt agarstaphlococci
Chemicals :Potassium telluriteTellurite blood agarCorynebacteria
Antimicrobial agents : [Antibiotics]Neomycin blood agar [Clostridia]Thayer-Martin medium
Changing the PH :-Alkaline peptone water : VibriosSabouraud medium : Fungi
5- Enrichment media :-Definition :Selenite F broth : Salmonella
6- Specialized media :- Definition : Identification mediaAntimicrobial Susceptibility Testing media
7- Transport media :-Definition :PreservationBuffers - Glycerol - Charcoal - Sod.thioglycolateStaurt - Amies - Cary - Blair
Preparation of media
1- Weighing & dissolving :PrecautionsHygroscopicDist. or diionized waterCapacity of the containerString or rotating
PH testing :-PH meterNarrow range PH paper
Sterilization :-AutoclaveSteamingFiletration
Addition of heat sensitive ingredients :-Waterbath 45⁰c - 50⁰c
Dispensing :-Petri - dishes containers
Quality control :-Control strains
Storage :-Refrigerator 2⁰c - 8⁰c
top related