I examine the results of studies that used mathematical models of the epide
miology and population genetics of antibiotic treatment and resistance in o
pen communities and in hospitals to explore the following issues: the relat
ionship between antibiotic consumption and the frequency of antibiotic resi
stance in bacterial populations in communities and in hospitals; methods of
controlling the growth, dissemination, and persistence of antibiotic resis
tance in these settings; the extent to which resistance can be controlled;
and the speed with which the effects of control measures will be realized.
In open communities, it will take years or even decades to see substantial
reductions in the frequency of antibiotic resistance solely as a result of
more prudent (reduced) use of antibiotics. However, if we can restrict the
input of resistant bacteria into hospitals, through the application of infe
ction control and other measures, it should be possible to reduce the frequ
ency of resistance and even eliminate resistant bacteria from these institu
tions in short order.