Recognize the morphology and culture characteristics of Clostridium tetani, Clostridium perfringens and Clostridium botulinum, and understand the pathogenicity of Clostridium perfringens through the "raging fermentation" test and animal test; understand the commonly used anaerobic culture method, and observe the pathogenic effect of tetanus exotoxin.
Operation method
Morphological observation of Clostridium anaerobicum
Principle
Clostridium difficile anaerobic germ cells are all Gram-positive, can form bud cells, its shape, size and location vary according to strains, can be used as a reference for strain identification; nutritional requirements are not high, but need anaerobic environment in order to grow. Common pathogenic bacteria are Clostridium tetani, Clostridium perfringens and Clostridium botulinum. Tetanus and gas gangrene are serious traumatic infections, especially important in wartime. Clostridium botulinum is the causative agent of food poisoning. Move 1. Observe slices of Clostridium tetani, Clostridium botulinum germ cell stained specimens and Clostridium perfringens pod stained specimens. For more product details, please visit Aladdin Scientific website.
2. Observe the growth characteristics of Clostridium tetani, Clostridium perfringens in botrytis medium and colony characteristics on blood plates.
3. Observe the growth characteristics of Clostridium perfringens and Clostridium tetani in glucose high-level agar medium (pay attention to the characteristics of gas production), and recognize the phenomenon of "raging fermentation".
Clostridium perfringens grows in glucose high-level agar medium and breaks down glucose to produce acid and a large amount of gas. The gas washes away the semi-solid agar (agar breaks into segments) and washes the petroleum jelly towards the mouth of the test tube; Clostridium tetani grows in this medium without any of the above.
In milk medium, Clostridium perfringens breaks down lactose and produces acid, which changes the bromocresol violet indicator from violet to yellow. The large amount of acid coagulates the casein, and the large amount of gas produced disperses the coagulated casein and rushes the Vaseline towards the mouth of the test tube. This phenomenon is called the "raging fermentation" phenomenon.