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