Dear researchers,
I’m conducting an experiment where I wish to have 10^4 CFU S. aureus in 2uL suspension.
I need to measure the concentration of bacterias in the suspension immediatly before i inoculat a sample.
How do i calculate this?
My idea is to use OD to convert to CFU.
Thank you for your help.
I like your idea but I am concerned that, since using the OD vs concentration is once removed, this approach will introduce additional error. You will need to perform multiple dilutions of known CFUs around your target to develop the look-up curve. That's a significant amount of pre-work.
Perhaps an easier and more accurate way would be to use a flow cytometer continuously sampling your homogenous suspension (stirred). Adjust your suspension to your target 5 E3/µL count, draw up 2microliters, and dispense knowing with some certainty that you are drawing at the same concentration that is reported by the flow cytometer. I think you will enjoy this video: https://www.youtube.com/watch?v=3S2N95xb_0Q
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