Biometrics of the grading of antibiotics

Biometrics
of antibiotic property price 1, the purpose requiresto learn the basic principles and methods of biometrics (tube method) of antibiotic effective.II, FundamentalsSome
microbials
produce secondary metabolites in the metabolic process that inhibit or kill certain microorganisms at low concentrations, a substance called antibiotics.the grading of antibiotics have dilution method, turbidity method and diffusion method.
tube dish method is one of the diffusion method, this method is the use of antibiotics in
agar
culture
-based diffusion osmosis, the known concentration of standard solution and unknown concentration of sample solution in the agar surface containing sensitive test bacteria diffusion penetration, compare the two on the antibacterial effect of the bacteria under examination, to find out the size of the anti-bacterial circle, in order to determine the concentration of antibiotics.
In a certain range, the concentration and the diameter of the antibacterial ring are in a straight-line function on the bi-weekly half-pair table (concentration is a pair of values, the diameter of the anti-bacterial circle is a numerical value), thus drawing a standard curve, from the size of the sample anti-bacterial ring can be obtained on the standard curve of its effective value.
Because this method is the use of antibiotics to inhibit the characteristics of sensitive bacteria, so in line with the actual situation of clinical use, and sensitivity is also very high, no special equipment, so the general laboratory and production of more use of this method. However, this method also has disadvantages, that is, many steps, complicated procedures, long training time, slow results. Nevertheless, because of its unique advantages mentioned above, it has been recognized all over the world as an internationally accepted method that is included in the scope of national pharmacopeia regulations.this experiment used the property price determination of tomycin produced by Streptomyces rimosus as an example.3, equipmentyellow octaccococcal (Sarcina flava);(tomycin price determination)
culture
,(for culture test bacteria) medium I.,(for the upper and lower layers of spread double discs) medium II.;Petri dish, Oxford Cup (or rust-free steel pipe), terracotta cover, 50ml, 250ml, 1000ml
capacity bottle
, 0. 1mol/LHCl, tomycin
standard
etc., the operation step 1. pH6． 0 Phosphoric acid buffer preparation accurately named KH2 PO4 0. 8g and K2 HPO4 0. 2g, in a 100 ml capacity bottle, diluted with distilled water to the scale, sterilized standby. 2． Preparation of standard tomycin solution exactly named 20 mg of tomycin standard, containing 880 units (880r/mg) per milligram, first with 0. 1mol/LHCl dissolves (1 ml of acid per 10 mg by weighing) and then dilutes the sterile distilled water into a solution containing 1000 units (1000r/ml) per milliliter, which is stored below 5 degrees C. 3． The preparation of the sample solution under accurately called the sample about 20 mg, first with 0. 1mol/LHCl2ml dissolved, then diluted with sterile distilled water to an estimated 1000 units per milliliter, and then absorbed 1 ml to 50 ml capacity bottle plus pH6. 0 Phosphoric acid buffer to scale, diluted to an estimated 20 units per milliliter of sample solution. 4． Preparation of yellow octaccococcal fluid take the yellow octaccococcal species, which are inoculated once a week and preserved with ordinary agar slope, and the bacteria are inoculated on the
tubt tube
slope containing culturer II. 5． The preparation of the dual disc takes 90mm in diameter and 27 in the double disc with a height of 15mm, and injects the dissolved culturer II.20ml, shakes well, and places the horizontal position to solidify as the bottom layer. Another culture base II., after dissolution cold to 48-50 degrees C, add the above-mentioned yellow octaccoccal liquid appropriate amount (to be able to clear the bactericide ring, so that every 1 ml containing 20 units of the standard liquid of the soilmycin caused by the diameter of the anti-bacterial circle in 15-18 mm is suitable), quickly shake well, in each double dish to add 5 ml of this bacteria-containing medium, so that on the bottom layer evenly spread, as a layer of bacteria, placed horizontal position to be solidified, in each two dishes at an equal distance to place the Oxford Cup 6 evenly, covered with a terracotta cover spare. 6． Preparation of the standard curve take 50 ml capacity bottle 9 numbers, and add different amounts of each milliliter containing 1000 units of standard solution, with phosphoric acid buffer released to the scale, so that each milliliter containing soil mold 8, 10, 12, 16, 20, 24, 28, 32, 36 units of 9 concentrations of standard dilution (table X.3).
Take the above-mentioned preparation of 24 double discs, each of the six Oxford Cup interval of 3 cups each containing 20 units of standard dilution per milliliter, each of the 3 double discs into a group of 8 groups. In the first group of 3 double disc empty cups each loaded with 8 units of standard dilution per milliliter, the second group of empty cups containing 10 units of standard dilution per milliliter, in turn, 8 concentrations of standard dilution.
total of 20 units per milliliter of standard dilution 72 cups, other dilution of the standard products each get 9 cups, all double-disc cover on the ceramic tile round cover rear 37 degrees C culture 16-18 hours. Measuring the diameter of each antibacterial ring, the average of 20 units of standard bactericide ring diameter and other concentrations of standard bactericide ring diameter was calculated in each group of 3 double dishes, and 20 units of standard product per milliliter were calculated. The total average of the diameter of the antibacterial ring, the difference between the total average and the average of the diameter of the bactericide ring containing 20 units per milliliter in each group, that is, the correction number of each group, according to the correction number of each group will be the average of 8 concentrations of anti-bacterial ring. example: if 8 groups containing 20 units per milliliter of standard antibacterial ring diameter total average of 17. 0mm, while 9 of the group with 12 units per milliliter contained 20 units per milliliter had an average diameter of 16. 8mm, the correction number should be 17. 0-16． 8=0． 2, if 9 per milliliter containing 12 units of standard antibacterial ring diameter of an average of 16. 4mm, then the correction should be 16. 4 0． 2=16． 6（mm）。 With concentration as the ordinate, the diameter of the corrected antibacterial ring is the horizontal coordinate, and the standard curve is drawn on the bi-weekly and half-pair drawings. 7． The assay method took the above-mentioned prepared double disc 3, in each of the 6 Oxford Cup interval 3 cups containing 20 units of standard dilution per milliliter, the other 3 cups each loaded with an estimated 20 units per milliliter of sample solution, covered with terracotta cover, set 37 degrees C culture 16-18 hours, measuring each antibacterial ring Diameter, respectively, to find the standard dilution and sample solution caused by the average of the diameter of the 9 bactericide ring, according to the above standard curve preparation method to find the correction number, the sample solution caused by the bactericide ring diameter of the average correction, and then from the standard curve to find the effectiveness of the sample solution, and converted to the sample under test per milligram contained units. , the experimental report 1. Results the effective price of the sample under test is how many units per milliliter? 2． Question: (1) What are antibiotics? How many mechanisms do it have for microorganisms? For example. (2) antibiotic property price determination, why commonly used tube and dish method to determine