Bacterial susceptibility test to antibiotics

In normal human blood, urine, cerebrospinal fluid, pleural fluid, pericardial fluid and peritoneal fluid, no bacteria exist. Basic Information Specialist classification: Infectious disease examination and classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: When experimenting, be sure to establish the concept of “no antibiotic operation”. Normal value Sensitive is recorded as (S). Zhong Min is recorded as (I). Resistance is recorded as (R). Clinical significance Reflects the extent to which an antibiotic is bacteriostatic to the bacterium. Clinically, the physician is instructed to use antibiotics correctly, avoiding repeated use of antibiotics that have developed resistance. Precautions 1. The test strain should be highly sensitive to the antibiotic being tested. 2. The test strains issued by the drug testing institute are freeze-dried products, which are stored in a refrigerator at 5-8 ° C, and can generally be stored for 1 to 3 years. 3. When experimenting, it is necessary to establish the concept of “no antibiotic operation”. 4, sulfa drugs use a flawless agar plate, due to protein will make sulfonamide lose its effect. Inspection process There are three ways in which bacteria can be tested for antibiotic resistance. Diffusion method Agar is added to the various nutrients required by the bacteria. After the medium is melted, it is poured into a sterile Petri dish, cooled, and condensed into a flat surface or plate (plate). At this time, the bacterial liquid containing a small amount of bacteria is applied to the plate, and after the culture, the bacteria will be separately swelled on the plate. If the antibiotic paper is added in advance in the medium of the plate, the drug is diffused in the medium, and the inhibition is caused. The effect of (killing) bacteria forms a ring of inhibition of colonies that are not long. The size of the inhibition circle reflects the extent to which an antibiotic inhibits the bacteria. 2. Dilution method Commonly used drug-sensitive dilution method can be divided into two methods: tube dilution method and agar dilution method. (1) In the test tube dilution method, the test antibacterial drugs are first diluted in series, and then the test tube liquid is appropriately diluted in each test tube, shaken, and observed after culture, with the minimum inhibitory concentration (MiC) tube of the antibacterial drug, that is, To test the sensitivity of the strain. (2) Agar dilution method Add different doses of antibacterial drugs to the quantitative agar medium which is melted and cooled to 45 ° C, mix and pour into a sterile plate, which is a medium containing decreasing drug concentration, inoculation test The bacteria are cultured on the medium, and the growth of the test bacteria is observed after the culture, and the minimum drug inhibits the growth of the bacteria, that is, the minimum inhibitory concentration (Mic). 3. Automatic analysis The domestic use of AUTOBAC instrument for the determination of bacterial susceptibility, the instrument is determined by measuring the low-loop drug, oscillating machine and photometer host, according to drug resistance, moderate resistance, sensitivity, and the minimum inhibitory concentration is printed. This instrument is only suitable for the determination of aerobic and facultative anaerobic bacteria, not suitable for the examination of obligate anaerobic bacteria and Mycobacterium tuberculosis. Not suitable for the crowd Generally there are no people who are not suitable. Adverse reactions and risks May cause an infection.

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