PK/PD and point mutations ...
The "Mutant Prevention Concentration" *
"When Mycobacterium bovis BCG and Staphylococcus aureus were plated on agar containing increasing concentrations of fluoroquinolone, colony numbers exhibited a sharp drop, followed by a plateau and a second sharp drop.
The plateau region correlated,vith the presence of first-step resistant mutants. Mutants were not recovered at concentrations above those required for the second sharp drop, thereby defining a mutant prevention concentration (MPC).
The MPC / MIC ratio is usually 10, but a C8-methoxy group lowers it to ? 3 for N-1-cyclopropyl-fluoroquinolones
Dong et al; AAC 43:1756-1758