Identification of bacteria

The identification of bacteria is a test of all aspects of the bacteria. For example, bacteria test various tests such as carbohydrate metabolism test, sputum test, and hydrolysis of starch. Basic Information Specialist classification: Digestive examination classification: biochemical examination Applicable gender: whether men and women apply fasting: not fasting Tips: To maintain good work habits, pay attention to normal eating habits. Normal value The normal flora of the gastrointestinal tract can be divided into aerobic bacteria, facultative anaerobic bacteria and anaerobic bacteria. The most dominant are anaerobic bacteria, which account for 99% of the total bacterial population, of which only Bacteroides and Bifidobacteria account for 90%, while Lactobacilli and Bifidobacteria can be with us for the rest of our lives. The types and proportions of these normal flora are normal. Clinical significance Some bacteria can decompose tryptophan and can react with dimethylaminobenzaldehyde to form red rose mites, so the strain can be identified based on whether the bacteria can decompose tryptophan to produce sputum. Abnormal results: 1. The internal environment of the intestine is not in dynamic equilibrium, and the proportion of normal bacteria is imbalanced. Pain, stomach acid, bloating, diarrhea, abdominal pain, falling, pus and bloody stools, etc., can cause gastrointestinal bleeding, perforation, and cancer, such as stomach cancer and colon cancer. 2. Escherichia causes an extraintestinal infection, especially a urinary tract infection. Citrobacter genus causes primary citrate pneumonia or secondary bacillus pneumonia. Pathological changes mainly manifested as bronchial pneumonia, which may have small abscess formation and focal hemorrhage. Clinical symptoms such as respiratory infection, sepsis, purulent meningitis, and urinary tract infection caused by Klebsiella. There are also various abnormal symptoms caused by Salmonella, Proteus, and the like. 3. Some bacteria hydrolyze starch and use its hydrolysate, which produces acid-producing gas and causes discomfort to the human body. People who need to be examined: those with various bacterial infections such as gastrointestinal bleeding, perforation, and canceration. Precautions Taboo before the test: To maintain good work habits, pay attention to normal eating habits. Requirements for inspection: Actively cooperate with the doctor. Inspection process I. test Method: The fresh slant culture of the test bacteria was inoculated with the inoculating loop in the Deng Hei's peptone solution, and cultured at 37 ° C for 24 to 48 hours (may be extended for 4 to 5 days). Add 2 to 3 ml of pentanol or xylene to the culture solution, shake well, and let stand for a while, then add 2 ml of the reagent along the tube wall. A liquid that turns red under pentanol or xylene is a positive reaction. You can also add two drops of Ourich's reagent to the large absorbent cotton, and add two drops of potassium persulfate (K2S2O4) in the same place in the same place. Place it in the test tube containing the culture solution, about half of the liquid surface. Inch, the red water is positive on the cotton wool after the water bath in the beaker is boiled. This method is slightly complicated, but the reagent is accurate and accurate, because the reagent is added to the liquid, and both sputum and skatole are positive, and in this method, only 吲哚 (which can be volatilized) is positive. The filter paper may also be wetted with a 1% solution of dimethyl benzene propylene formaldehyde in 10% concentrated HCl, and then a pure culture of a ring of agar scraped off with a loop of inoculum applied to the filter paper. The bacteria were stained blue and positive, and there was no color change around the bacterial print or negative yellow. 2. Hydrolysis of starch Starch can be hydrolyzed under the catalysis of acid; the hydrolysis process of starch: a dextrin with a smaller molecular weight (product of incomplete hydrolysis of starch), dextrin continues to hydrolyze to form maltose, and the final hydrolysate is glucose. Pair of agents: potassium iodide 2g distilled water 300ml Medium: The bacteria were inoculated on a plate, cultured in a 37-degree incubator for 24 hours, and Gram's iodine solution was added to the colony to observe the color change. The blue color was negative and no blue was positive. 3. β-galactosidase test Reagent: 0.75 MONPG solution: 80 mg was dissolved in 15 ml of distilled water, and 5 ml of a buffer (6.9 g of NaH 2 P04 dissolved in 45 ml of distilled water, adjusted to pH 7.0 with 30% NaOH, and then added with water to 50 ml) was placed in a refrigerator at 4 ° C in a refrigerator. METHODS: Pure colonies were prepared with sterile saline to prepare a concentrated suspension of bacteria. 0.25 ml of ONPG solution was added, and the mixture was placed in a water bath at 35 ° C for 20 min to 3 h. The results were observed. The result was judged: the color was usually developed within 20 to 30 minutes. A yellow color is positive. Not suitable for the crowd Inappropriate crowd: temporarily unknown. Adverse reactions and risks There are no related complications and hazards.

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