Economics of antibiotic resistance: A theory of optimal use

In recent years bacteria have become increasingly resistant to antibiotics, leading to a decline in the effectiveness of antibiotics in treating infec tious disease. This paper uses a framework based on an epidemiological mode l of infection in which antibiotic effectiveness is treated as a nonrenewab le resource. In the model presented, bacterial resistance (the converse of antibiotic effectiveness) develops as a result of selective pressure on non resistant strains due to antibiotic use. When two antibiotics are available , the optimal proportion and timing of their use depends precisely on the d ifference between the rates at which bacterial resistance to each antibioti c evolves and on the differences in their pharmaceutical costs. Standard nu merical techniques are used to illustrate cases for which the analytical pr oblem is intractable. (C) 2000 Academic Press.