The outcome of treating bacterial infections with antibiotics is a function of multiple variables. Factors that impact therapeutic efficacy include bacterial susceptibility to the antibiotics, physico-chemical properties of the drug product, specific properties of the infected tissue, metabolism and elimination of the antibiotic, host factors, and dosing regimen. Vogelman and Craig 1 stated in 1984: “To a large extent many of the early questions about dosing remain unanswered”. Today, this statement remains essentially valid. Dosing regimens are often based on trial and error rather than on rational design. Susceptible infections may not be eradicated even though the antibiotic dose is titered to produce serum concentrations within the recommended range. Some of the central questions for addressing this problem are

What factors govern antibacterial activity?

How can antibiotic efficacy be quantified to permit reliable comparison between different antibiotics?

How can efficacy of antibacterial treatment be optimized?