Pharmacokinetics (PK) and pharmacodynamics (PD) are two central terms within the area of setting breakpoints. Whenever there is sufficient evidence EUCAST will always define a PK-PD-breakpoint. This breakpoint will not take into account MIC-distributions of various species, but will rather inform regarding which MICs would be theoretically possible to treat from a pharmacological point of view. The document describes that only the free fraction of antimicrobials is pharmacologically active, and describes also the parameters describing best killing of bacteria. The pharmacodynamic parameters are either time of the dosing interval when the free concentration of the antimicrobial is above the MIC (fT>MIC) or the area under the serum concentration curve (fAUC/MIC). In the past the maximal serum concentration (Cmax) was also considered, but as of recent years this parameter is normally not considered, and is also largely overlapping with fAUC/MIC.
The Swedish Reference Group for Antimicrobials has a document describing the various pharmacodynamic parameters and also presenting som arithmetic examples of how these can be utilised when you have access to MICs and serum concentrations. The document is from 2009 and has not been systematically updated, but is still considered reliable with the exception of still using arithmetic examples with fCmax/MIC for aminoglycosides.
A link to the document is available here: https://forening.sls.se/media/xmpjq5gf/raf-rationaldokument-dosering-2009-1.pdf
Other relevant links regarding breakpoints: