Nutrient Broth

Nutrient Broth: these media is used for growing fastidious bacteria that is an organism that is not too difficult to cultivate. These media are basal media, in such case use as basal media for blood agar in the laboratories, the media composed of the following constituent;

Peptone 10g

Sodium chloride 5g

Beef extract 10g

Distilled water 100ml

Meat extract broth

Meat extract broth: as the name implied, the media is prepared from an extract gotten from meat with mixture of nutrient broth. These are commercially made with the dissolved of these extract in distilled water with peptone.

Serum broth

Serum broth: this is made up of serum plus nutrient broth.

Chocolate Broth

Chocolate Broth: this is made by heating animal blood plus nutrient broth together at a temperature of 70-80 ºC till chocolate color developed the rest of the media are;

1. Glucose broth
2. Infusion broth

• Nutrient agar

1. Digest broth

Glucose broth

Glucose broth: these are made up of glucose and nutrient broth. Both of the substance is co-formulated to give glucose broth.

Infusion Broth

Infusion Broth: the media is prepared from mice meat in water over night with temperature not exceeding or below 4 ºC.

Digested Broth

Digested Broth: this is a media prepared from mice meat place in water over night. And treated with carbonate which renders the sarcolactic acid in the meat power less and the meat is digested in trypsin.

Blood, chocolate, fildes, glucose, serum broth are all enrich media.

Filde Broth

Filde Broth: these are made up of nutrient broth in combination with 5% fildes media.

Furthermore, nutrient agar is used for further production of some media, such as serum agar, blood agar, chocolate agar, fildes agar, glucose agar etc.

The media are prepared by melting down nutrient agar and left to cool to a temperature of 49 ºC after which the enriched media is added. These media produce from nutrient agar are used for some specific purpose, i.e. such as blood agar used for cultivation of streptococcus, gonococci. Function of this media produce from nutrient agar is;

Blood agar

Blood agar: blood agar is made up of nutrient agar plus horse blood. They are mostly used as a differential media which is used for cultivation of organism that is more delicate such as gonococci, and streptococcus. The preparation of the culture plate has two methods which are;

1. Nutrient agar are melted by steaming the media, the steaming is achieved by the used of autoclave. After that it left to cool to 49 ºC at room temperature, then sterile of defibrenated blood is added 15-20ml volume of the media is pour into sterile petri dish which will followed by plate inoculation method.
2. Thin layer of is pour into a sterile petri dish and allowed to set and then add blood agar. It was suggested that this method is more adopted compare to that of first method, because when hemolysis take place it easily seen and blood agar is uniform in these method compared to that of first method, but doe to flat bottom of petri dish now laboratories preferred first method.

Glucose agar

Glucose agar: these are made up of nutrient agar and glucose. The compositions are dissolved in distilled water sterilized by filtration. In a aseptic condition, specific amount of glucose is taken and melted in which agar is added to give a final solution. Distribute the media on petri dish or bottle, tube for inoculating procedure.

Note: in a slope culture, it necessary that when media is poured on a bottle or tube, it should be left for 20 minute via sloping the plate.

Chocolate agar

Chocolate agar: This method is the same of that of chocolate broth explain above, but agar the different is that nutrient agar is used hears. This media is used for cultivation of some certain micro organism such as pneumococci, and Haemophilus influenza. For plate preparation after these media is produce by adding blood to nutrient agar and heat at a temperature of 70-80 ºC until chocolate color develop, and after that bring the media to cool at room temperature to that 49 ºC before aseptic procedure is followed to pour it on a plate. For Heamophilus influenza it required two factor which is facto x and factor v. factor x is haematin and factor v is (NAD) Nicotinamide Adenine Dinucleotide. But blood contain enzyme called NADase which break down (NAD) in these cas a little of these factor is left for bacteria to absorb. So because of the phenomenon blood is heated, when blood is heated the enzyme is deactivated, now leave available number of (NAD) for the bacteria to absorb and yield a normal growth. But there are already prepared pour plate today which many laboratories depend on.

Even with that it better to have knowledge on how to prepare these in the laboratory. Also there are available automatic pouring machine in the market which is used in many laboratory to save time, the machine is more secure and time saving, with used of the machine, the work can be carried out without supervision.

Nutrient gelatin

Nutrient gelatin: these are made up of nutrient broth plus gelatin

Composition

Nutrient broth 100ml

Gelatin powder 120-150ml

They are dissolved by heating in a steam condition, and the pH is check in other to achieve pH of 7.4. After these, sterilization takes place by steaming for at least 10 minute every day for three days. In other to obtain a clear gel these method can be follow. Clearing and filtering is not often important, but incase the media required clearing, add white component of rough egg and heat by steaming for 30 minutes. If there is any particle present, the particle will engulf to the coagulated egg, and then filter to remove the particles. In case of warm climate, high concentration of gelatin is required to produce gel.

Chocolate media

Chocolate media: there are several types of this media available commercially, but all most all the laboratory they prefer preparing their own media, in this case emphasis on the production of the media will be discussed. The power of different micro organism to ferment some carbohydrate is the major concept used in the examination and grouping of the organism. The most important is that these media must be free from all source of carbohydrate except the one which is specifically added. Nutrient broth is not recommendable to be added because it contained little quantity of muscle sugar. But peptone solution and sodium chloride can be added to the solution, the media is measure in tube or bottle, and these bottle or tubes will have durham tube. The durham tube must be inverted and filled with the indicator in the bottle or tubes. The indicator in the medium show the hiden production in the medium, before this take place the durham tube will be inverted and these inverted durham tube will trap any bubble of gas that are form in the medium, for delicate organism such as corynecbacterium dephtheriae, pneumococci, etc. the fermentation of the medium must be enriched with serum. But some other organism like meningococci and gonococci, they grow more preferable in a solid medium and for these agar is mixed with the serum sugar medium.