Antibiograms as one-health tools for antimicrobial stewardship: California's experience with livestock antibiogram development.

Antibiograms are collections of antimicrobial susceptibility data for a particular bacterial organism and host species. Antibiograms are important tools for antimicrobial stewardship, as they may be used to guide empiric antimicrobial therapy and assess trends in antimicrobial resistance, maximizing treatment success and preserving the efficacy of currently available pharmaceuticals. Targeted use of antimicrobials is critically important to minimize the spread of antimicrobial resistance, which may be conveyed between animals and humans directly but may also be spread through the environment and ecological niches, such as soil, water, and wildlife reservoirs. To effectively utilize antibiograms as part of a comprehensive antimicrobial stewardship plan, veterinarians need to know data characteristics, including the source population, body site (when possible), and number of isolates included, in addition to the animal species and bacterial organisms for which each breakpoint was developed. Although widely used in human health systems, antibiograms are not often available in veterinary medicine. This paper describes antibiogram creation and use, discusses antibiogram development by US veterinary diagnostic laboratories, and shares California's process to create and promote livestock antibiograms. The companion Currents in One Health article by Burbick et al, AJVR, September 2023, addresses the benefits and challenges associated with developing veterinary antibiograms.

Benefits and challenges of creating veterinary antibiograms for empiric antimicrobial selection in support of antimicrobial stewardship and advancement of one-health goals.

Antibiograms are important tools for antimicrobial stewardship that are often underutilized in veterinary medicine. Antibiograms summarize cumulative antimicrobial susceptibility testing (AST) data for specific pathogens over a defined time period; in veterinary medicine, they are often stratified by host species and site of infection. They can aid practitioners with empiric therapy choices and assessment of antimicrobial resistance trends within a population in support of one-health goals for antimicrobial stewardship. For optimal application, consideration must be given to the number of isolates used, the timeframe of sample collection, laboratory analytical methodology, and the patient population contributing to the data (eg, treatment history, geographic region, and production type). There are several limitations to veterinary antibiograms, including a lack of breakpoint availability for bacterial species, a lack of standardization of laboratory methodology and technology for culture and AST, and a lack of funding to staff veterinary diagnostic laboratories at a level that supports antibiogram development and education. It is vital that veterinarians who use antibiograms understand how to apply them in practice and receive relevant information pertaining to the data to utilize the most appropriate antibiogram for their patients. This paper explores the benefits and challenges of developing and using veterinary antibiograms and proposes strategies to enhance their applicability and accuracy. Further detail regarding the application of veterinary antibiograms by privately practicing clinicians is addressed in the companion Currents in One Health article by Lorenz et al (JAVMA, September 2023).