Hi all,

I need to make MIC with imipenem. We have the 500 mg/500 mg Imipenem/Cilastatin Powder for Solution for Infusion. My question is: how do I calculate the quantity of powder for the antibiotic stock solution?and the volume of this? I need to test 5 isolates of Klebsiella pneumoniae with broth microdiluiton.
Since I need to use the Iso-Sensitest Broth to diluite my antibiotic , do I need to grow also my cells in this same broth overnight before doing the MIC?
If I choose to use the agar dilution plate method, can I test different isolates of the same bacterium in the same diluited plate in your opinion?
Sorry for my stupid questions but I am completely new in that.
Thank you in advance.

Silvia

As CharonY mentioned in your other thread, these are probably things you should be getting specific in-house training for.

 

How much antibiotic you use depends on what concentrations you think you should be working at. I think this is species and antibiotic dependant, so I would be asking your supervisor about this.

 

I have only ever done MICs in 96 well plates using colonies picked from plates and diluted to a particular OD or CFU, but in this I have generally always used 4uL of antibiotic stock solution to get to my desired final concentration (meaning that my stock is 50x this concentration) and 1:2 dilutions thereafter across the plate. I think this is fairly routine, though I am quite new to microbiology.