Pre-diffusion of agar plates seeded with bacteria and inoculated disks for disk diffusion assay.
Dear What kind of experiment you want to perform?
I don't think so to keep the Petri dishes to be inverted.
So why you should keep your plate at 4 degree. If you will note your results and analysis done according to CLSI guidelines than you just keep photographs with you.
No once we put the disk we keep it at Room temperature for 10-15 minutes for diffusion then incubate to appropriate air no need of 4oc
We kept plates at 4 degree in refrigerator so that the compound (antimicrobial agent) will easily diffuse into the agar medium and also no bacterial growth will occur at this temperature. But we do not invert the plates.
Diffusion occurs once the impregnated discs are placed on the agar surface. Therefore there is no need for inversion or possibly refrigeration
Iniobong James I agreed, but the diffusion in the agar varies from compound to compound. Some needs more time to diffuse.
Mac Dz I do not invert the plates while doing disc diffusion assay but in other cases i invert them to avoid moisture. Also, in case of agar well diffusion assay it is not correct to invert the plates.
Rajanbir Kaur : Thanks for the answer. How do you avoid moisture without inverting the plates in the disc diffusion assay. Once parafilm is applied moisture builds up. Then I guess have to try one plate without inverting to see whether moisture doesn't interfere with the experiment.
Mac Dz I do not seal the lid of the petriplates completely. So little or no moisture build up. Also, while growing aerobic bacteria it is not correct to fully seal the petriplates
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