A randomised controlled trial to reduce highest priority critically important antimicrobial prescription in companion animals

Abstract Robust evidence supporting antimicrobial stewardship schemes in companion animals is limited, despite frequent highest priority critically important antimicrobial (HPCIA) prescription. In this randomised controlled trial, electronic prescription data were utilised (August 2018–January 2019) to evenly assign 60 above average HPCIA-prescribing practices into a control group (CG) and two intervention groups. In March 2019, the light intervention group (LIG) and heavy intervention group (HIG) were notified of their above average status, and were provided with educational material (LIG, HIG), in-depth benchmarking (HIG), and follow-up meetings (HIG). Post-intervention, in the HIG a 30% and 42% significant reduction in canine (0.5% of consultations, 95% confidence interval, 0.4–0.6) and feline (4.4%, 3.4–5.5) HPCIA-prescribing consultations was observed, and maintained for three and six months, respectively, compared to the CG (dogs: 0.7% (0.5–0.8); cats: 7.6% (6.1-9.0)). The LIG was not associated with significant variation. This evidence is now informing development of a national stewardship scheme.