Antibiotic prescribing decisions of generalists and infectious disease specialists: thresholds for adopting new drug therapies.

The objective of this study was to examine whether physicians are willing to continue to use older antibiotics in the face of drug resistance in order to preserve newer antibiotics forfuture use. The study was a national sample of 398 generalist physicians and 429 infectious disease (ID) specialists. Clinical vignettes prompted respondents to select the level of resistance to a hypothetical older antibiotic at which they would prefer a newer antibiotic without any current resistance in the treatment of a patient with pneumococcalpneumonia. Vignettes varied in the site of care of the patient as a proxyfor variation in disease severity. Respondents significantly reduced their threshold for switching to a newer antibiotic as disease severityincreased. Generalists were more responsive to disease severity than LD specialists. Thus, the adoption of recommendations to limit overuse of newer antibiotics may be variable across clinical settings and providers, reducing the impact of these recommendations on emerging resistance.