In recent years, researchers have made substantial progress in the development of methods to measure the burden of resistance and the application of those methods to the limited data available. Our understanding of the costs incurred by patients infected with resistant strains in hospital settings is much better than it was 10, or even 5, years ago. Research on the impact of resistance in the community is more limited. When multiple treatment options are available and prescribed treatment is empirical, resistance will lead to higher expenditures on drugs but not necessarily to increased patient morbidity and mortality. Understanding to what degree prescribing patterns are driven by real versus perceived limitations of first-line drugs is important for assessing the ability of public health campaigns to change the behavior of patients and providers.