Chocolate plate medium is mainly used for the isolation and culture of aerobic bacteria such as Neisseria spp. and Haemophilus spp. Chocolate plate should be prepared by sheep blood or blood free. Because it contains X and V factors, Haemophilus, Neisseria, etc. grow well, all specimens suspected of the presence of these strains must be inoculated with chocolate plate. Blood specimen culture, seedling increase after a fine seedling growth, if transferred to the chocolate plate, is conducive to the isolation of more bacteria. This experiment is from Mudanjiang Medical College, undergraduate 5-year laboratory guide for testing majors.
Operation method
Chocolate plate preparation
Principle
Mainly peptone and beef meal are used to provide carbon and nitrogen sources, amino acids, and vitamins for bacterial growth. Sodium chloride maintains osmotic pressure in the medium and agar is used as a coagulant. Defibrinated sheep blood provides heme chloride and coenzyme I, which provide special nutrients for the growth of Haemophilus spp. Chocolate plate medium is also able to culture other bacteria, the main reason is that the blood has V, X factor, these two factors are located in the red blood cells, the general bacteria can not be utilized, a slight heating (usually about 75 ~ 85 degrees Celsius) so that the destruction of red blood cells to be released to the outside of the cell can be utilized.
Materials and Instruments
Defibrinated sheep or rabbit blood Move I. Main ingredients of chocolate plate 1. Prepared from sheep blood Peptone 10g Beef powder 3g Sodium chloride 5g Defiberized sheep blood 50mL Agar 15g Distilled water 1000mL 2. Preparation with rabbit blood Fresh beef leachate 1000mL Peptone 10g Sodium chloride 5g Defiberized rabbit blood 100mL Agar 15g Chocolate plate preparation 1. Mix the main ingredients except defibrillated sheep blood (rabbit blood), correct the pH at 7.2--7.4, autoclave and then cool to 85℃. 2. aseptically add defibrinated sheep blood (rabbit blood), shake well and place in a water bath at 85°C, maintain this temperature for 10 minutes to make a chocolate color. 3. Remove, cool to approximately 50°C at room temperature and decant the plate. Caveat 1. Appearance: The chocolate plate medium should be chocolate-colored solid, with a flat surface and no cracks. And the medium should not have visible bubbles and visible matter (but a small amount of visible fiber is allowed). 2. pH value should be 7.2±0. 2. 3. Asepsis requirements: put the chocolate plate culture medium in 37℃±2℃ incubator for 7 days, there shall be no bacterial growth. Common Problems This experiment is from Mudanjiang Medical College, Laboratory Guidance for Inspection Specialties. For more product details, please visit Aladdin Scientific website.
Peptone Beef meal Sodium chloride Agar Distilled water
Glass dishes Measuring cylinders Autoclave pH meter 85℃ water bath Ultra-clean bench Weighing balance