What conditions must be held constant when doing disc diffusion procedures?

Answer 1

Conditions that must be constant from test to test

include the agar used, the amount of organism used, the concentration of

chemical used, and incubation conditions (time, temperature, and atmosphere)

Answer 2

This is also called the Kirby Bauer test. This proceedure is usually used when testing with micobes or bacteria. For this proceedure, you will first have to gather all of your materials. The main thing you will need are agar plates, diffusion disc, something to spread bacterisa (clean q-tips can work), forcepts or tweezers, the bacteria you are using, and the subtance you will put on the diffusion discs.

1. Sure you have followed steps with being safe with bacteria and the substances you are using.

2. Bacteris is uniformly spread around and across the agar plate using a spreader. Put the lid on the agar plate as soon as the bacteria has been spread across the plate.

3. Wait 5 minutes for the surface to dry.

4. Remember to have a negative control (water). ( Dip a different sterile disk into each substance being tested. If the substance is a liquid then shake the disk to remove access liquid. If the substance is a cream or gel use a sterile cotton swab to remove access substance.

5. Place the disk in the middle of an appropriate quadrant of the agar plate. Using the forceps or tweezers press down on the disk to ensure proper contact.

6. remember to sterilize the forceps each time you change substances; whiping with ethanol then setting over a flame)

7. Incubate the plates at 37 derees Celcius for 48 hours. If you do not have an incubator leave plate at room temperature away from direct sunlight; (maybe in a warm part of the house in a plastic bag next to a heating vent). Extend time to between 72-96 hours.

Remove and examine your plate :)

Answer 3

When performing disc diffusion procedures, it is crucial to keep certain conditions constant to ensure accurate results. These conditions include the temperature of incubation, the concentration of the test microorganism, the depth of agar in the petri dish, and the size and type of the culture medium used. Maintaining consistency in these factors will help standardize the procedure and allow for meaningful comparisons between different samples.