beta-galactosidase assay

The β-galactosidase test is a test method in which some bacteria can produce β-galactosidase and decompose o-nitrophenol-βgalactoside (ONPG) to form a yellow o-nitrophenol. Basic Information Specialist classification: Infectious disease inspection and classification: biochemical examination Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Normal value: no Above normal: negative: Escherichia, Citrobacter, Klebsiella, and the like. Bacteria that do not ferment lactose, such as Salmonella, Proteus, etc., are negative. Positive: Intestinal infection of lactose that is slowly fermented. Tips: 0NPG solution is colorless, if it appears yellow, it should not be used again. Normal value The type and proportion of the flora in the body are normal, and the human body is in a state of dynamic balance and health. Clinical significance The enterobacteria ONPG test which delays the fermentation of lactose is positive, such as Escherichia, Citrobacter, Klebsiella and the like. Bacteria that do not ferment lactose, such as Salmonella, Proteus, etc., are negative. This test can be used as a rapid identification method for slow fermentation of lactose bacteria. Abnormal results 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. Patients in need of examination are infected with Escherichia, Citrobacter, Klebsiella, Salmonella, and Proteus. Positive results may be diseases: precautions for urinary tract infections Inappropriate crowd: No. Forbidden before examination: Pay attention to normal eating habits and pay attention to personal hygiene. Requirements for inspection: Actively cooperate with the doctor. Inspection process 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 no. Adverse reactions and risks no.