The utility of hospital antibiograms as tools for guiding empiric therapy and tracking resistance. Insights from the Society of Infectious Diseases Pharmacists.

Hospital antibiograms are commonly used to help guide empiric antimicrobial treatment and are an important component of detecting and monitoring trends in antimicrobial resistance. To serve these purposes, antibiograms must be constructed using standardized methods that allow inter- and intrahospital comparisons. Antibiograms that include surveillance cultures and duplicate bacterial isolates can overestimate rates of resistance. In 2002, the National Committee for Clinical Laboratory Standards (now known as the Clinical and Laboratory Standards Institute [CLSI]) published standards for constructing antibiograms. According to national surveys, many of the recommended elements of the CLSI document have not been fully adopted. In lieu of full compliance with CLSI standards, it is necessary that the methods used to construct antibiograms are clearly delineated. Antibiograms have several limitations, such as their inability to track emergence of resistance during therapy. The antibiogram can serve as a valuable tool in guiding antimicrobial therapy, but other patient factors, such as previous infection history and antibiotic use, also need to be considered. Additional data are needed for specialized applications of resistance analyses.