Reconciling differences between EUCAST 'breakpoint-defining doses' and UK national antimicrobial treatment guidelines

The British National Formulary and the NICE provide empirical treatment guidance for the management of various infections, including recommendations on antibiotic doses. In parallel, and for over 15 years, EUCAST has published details of the doses upon which their antimicrobial susceptibility breakpoints are predicated, termed here 'breakpoint-defining doses'. Recently, differences between these dosing recommendations have attracted attention, particularly since EUCAST introduced its 'susceptible, increased exposure' category of susceptibility. We discuss where and why these differences exist and how to reconcile them.